blob: 4e34f2439c727f11903495356967dc29f65ba862 [file] [log] [blame]
Darren Tucker7bd98e72010-01-10 10:31:12 +11001/* $OpenBSD: sshd.c,v 1.370 2010/01/09 23:04:13 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 Millere4340be2000-09-16 13:29:08 +11006 * This program is the ssh daemon. It listens for connections from clients,
7 * and performs authentication, executes use commands or shell, and forwards
Damien Miller95def091999-11-25 00:26:21 +11008 * information to/from the application to the user client over an encrypted
Damien Millere4340be2000-09-16 13:29:08 +11009 * connection. This can also handle forwarding of X11, TCP/IP, and
10 * authentication agent connections.
Damien Millerefb4afe2000-04-12 18:45:05 +100011 *
Damien Millere4340be2000-09-16 13:29:08 +110012 * As far as I am concerned, the code I have written for this software
13 * can be used freely for any purpose. Any derived versions of this
14 * software must be clearly marked as such, and if the derived work is
15 * incompatible with the protocol description in the RFC file, it must be
16 * called by a name other than "ssh" or "Secure Shell".
17 *
18 * SSH2 implementation:
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000019 * Privilege Separation:
Damien Millere4340be2000-09-16 13:29:08 +110020 *
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000021 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
22 * Copyright (c) 2002 Niels Provos. All rights reserved.
Damien Millere4340be2000-09-16 13:29:08 +110023 *
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
26 * are met:
27 * 1. Redistributions of source code must retain the above copyright
28 * notice, this list of conditions and the following disclaimer.
29 * 2. Redistributions in binary form must reproduce the above copyright
30 * notice, this list of conditions and the following disclaimer in the
31 * documentation and/or other materials provided with the distribution.
32 *
33 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
34 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
36 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
37 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
39 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
40 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
41 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
42 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Miller95def091999-11-25 00:26:21 +110043 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100044
45#include "includes.h"
Damien Miller17e91c02006-03-15 11:28:34 +110046
Damien Miller9cf6d072006-03-15 11:29:24 +110047#include <sys/types.h>
Damien Millerd7834352006-08-05 12:39:39 +100048#include <sys/ioctl.h>
49#include <sys/socket.h>
Damien Millerf17883e2006-03-15 11:45:54 +110050#ifdef HAVE_SYS_STAT_H
51# include <sys/stat.h>
52#endif
Damien Miller9aec9192006-08-05 10:57:45 +100053#ifdef HAVE_SYS_TIME_H
54# include <sys/time.h>
55#endif
Damien Millerd7834352006-08-05 12:39:39 +100056#include "openbsd-compat/sys-tree.h"
Damien Millerb84886b2008-05-19 15:05:07 +100057#include "openbsd-compat/sys-queue.h"
Damien Miller9cf6d072006-03-15 11:29:24 +110058#include <sys/wait.h>
Damien Miller03e20032006-03-15 11:16:59 +110059
Darren Tucker39972492006-07-12 22:22:46 +100060#include <errno.h>
Damien Miller57cf6382006-07-10 21:13:46 +100061#include <fcntl.h>
Damien Millerb8fe89c2006-07-24 14:51:00 +100062#include <netdb.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110063#ifdef HAVE_PATHS_H
Damien Miller03e20032006-03-15 11:16:59 +110064#include <paths.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110065#endif
Damien Millera1738e42006-07-10 21:33:04 +100066#include <grp.h>
Damien Miller9f2abc42006-07-10 20:53:08 +100067#include <pwd.h>
Damien Miller6ff3cad2006-03-15 11:52:09 +110068#include <signal.h>
Damien Millerded319c2006-09-01 15:38:36 +100069#include <stdarg.h>
Damien Millera7a73ee2006-08-05 11:37:59 +100070#include <stdio.h>
Damien Millere7a1e5c2006-08-05 11:34:19 +100071#include <stdlib.h>
Damien Millere3476ed2006-07-24 14:13:33 +100072#include <string.h>
Damien Miller75bb6642006-08-05 14:07:20 +100073#include <unistd.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100074
Ben Lindstrom226cfa02001-01-22 05:34:40 +000075#include <openssl/dh.h>
76#include <openssl/bn.h>
Damien Miller6a47f302002-02-13 13:55:06 +110077#include <openssl/md5.h>
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000078#include <openssl/rand.h>
Darren Tuckerbfaaf962008-02-28 19:13:52 +110079#include "openbsd-compat/openssl-compat.h"
80
Kevin Steves0ea1d9d2002-04-25 18:17:04 +000081#ifdef HAVE_SECUREWARE
82#include <sys/security.h>
83#include <prot.h>
84#endif
Ben Lindstrom226cfa02001-01-22 05:34:40 +000085
Damien Millerd7834352006-08-05 12:39:39 +100086#include "xmalloc.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000087#include "ssh.h"
88#include "ssh1.h"
89#include "ssh2.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100090#include "rsa.h"
Ben Lindstromd95c09c2001-02-18 19:13:33 +000091#include "sshpty.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100092#include "packet.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000093#include "log.h"
Damien Millerd7834352006-08-05 12:39:39 +100094#include "buffer.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100095#include "servconf.h"
96#include "uidswap.h"
97#include "compat.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000098#include "cipher.h"
Damien Millerb38eff82000-04-01 11:09:21 +100099#include "key.h"
Damien Millerd7834352006-08-05 12:39:39 +1000100#include "kex.h"
Damien Miller874d77b2000-10-14 16:23:11 +1100101#include "dh.h"
Damien Millerefb4afe2000-04-12 18:45:05 +1000102#include "myproposal.h"
Damien Millereba71ba2000-04-29 23:57:08 +1000103#include "authfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000104#include "pathnames.h"
105#include "atomicio.h"
106#include "canohost.h"
Damien Millerd7834352006-08-05 12:39:39 +1000107#include "hostfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000108#include "auth.h"
109#include "misc.h"
Darren Tucker645ab752004-06-25 13:33:20 +1000110#include "msg.h"
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +0000111#include "dispatch.h"
Ben Lindstrom1bae4042001-10-03 17:46:39 +0000112#include "channels.h"
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +0000113#include "session.h"
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000114#include "monitor_mm.h"
115#include "monitor.h"
Damien Millerd7834352006-08-05 12:39:39 +1000116#ifdef GSSAPI
117#include "ssh-gss.h"
118#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000119#include "monitor_wrap.h"
Darren Tuckerc5564e12009-06-21 18:53:53 +1000120#include "roaming.h"
Damien Millerb7576772006-07-10 20:23:39 +1000121#include "version.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000122
123#ifdef LIBWRAP
124#include <tcpd.h>
125#include <syslog.h>
Darren Tucker1f1e17b2008-02-28 23:20:48 +1100126int allow_severity;
127int deny_severity;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000128#endif /* LIBWRAP */
129
130#ifndef O_NOCTTY
131#define O_NOCTTY 0
132#endif
133
Damien Miller035a5b42004-06-26 08:16:31 +1000134/* Re-exec fds */
135#define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
136#define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
137#define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
138#define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
139
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000140extern char *__progname;
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000141
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000142/* Server configuration options. */
143ServerOptions options;
144
145/* Name of the server configuration file. */
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000146char *config_file_name = _PATH_SERVER_CONFIG_FILE;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000147
Damien Miller4af51302000-04-16 11:18:38 +1000148/*
Damien Miller95def091999-11-25 00:26:21 +1100149 * Debug mode flag. This can be set on the command line. If debug
150 * mode is enabled, extra debugging output will be sent to the system
151 * log, the daemon will not go to background, and will exit after processing
152 * the first connection.
153 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000154int debug_flag = 0;
155
Ben Lindstrom794325a2001-08-06 21:09:07 +0000156/* Flag indicating that the daemon should only test the configuration and keys. */
157int test_flag = 0;
158
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000159/* Flag indicating that the daemon is being started from inetd. */
160int inetd_flag = 0;
161
Ben Lindstromc72745a2000-12-02 19:03:54 +0000162/* Flag indicating that sshd should not detach and become a daemon. */
163int no_daemon_flag = 0;
164
Damien Miller5ce662a1999-11-11 17:57:39 +1100165/* debug goes to stderr unless inetd_flag is set */
166int log_stderr = 0;
167
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000168/* Saved arguments to main(). */
169char **saved_argv;
Damien Millerb8c656e2000-06-28 15:22:41 +1000170int saved_argc;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000171
Darren Tucker645ab752004-06-25 13:33:20 +1000172/* re-exec */
173int rexeced_flag = 0;
174int rexec_flag = 1;
175int rexec_argc = 0;
176char **rexec_argv;
177
Damien Miller5428f641999-11-25 11:54:57 +1100178/*
Damien Miller34132e52000-01-14 15:45:46 +1100179 * The sockets that the server is listening; this is used in the SIGHUP
180 * signal handler.
Damien Miller5428f641999-11-25 11:54:57 +1100181 */
Damien Miller34132e52000-01-14 15:45:46 +1100182#define MAX_LISTEN_SOCKS 16
183int listen_socks[MAX_LISTEN_SOCKS];
184int num_listen_socks = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000185
Damien Miller5428f641999-11-25 11:54:57 +1100186/*
187 * the client's version string, passed by sshd2 in compat mode. if != NULL,
188 * sshd will skip the version-number exchange
189 */
Damien Miller95def091999-11-25 00:26:21 +1100190char *client_version_string = NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000191char *server_version_string = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000192
Ben Lindstrom8ac91062001-04-04 17:57:54 +0000193/* for rekeying XXX fixme */
194Kex *xxx_kex;
195
Damien Miller5428f641999-11-25 11:54:57 +1100196/*
197 * Any really sensitive data in the application is contained in this
198 * structure. The idea is that this structure could be locked into memory so
199 * that the pages do not get written into swap. However, there are some
200 * problems. The private key contains BIGNUMs, and we do not (in principle)
201 * have access to the internals of them, and locking just the structure is
202 * not very useful. Currently, memory locking is not implemented.
203 */
Damien Miller95def091999-11-25 00:26:21 +1100204struct {
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000205 Key *server_key; /* ephemeral server key */
Damien Miller0bc1bd82000-11-13 22:57:25 +1100206 Key *ssh1_host_key; /* ssh1 host key */
207 Key **host_keys; /* all private host keys */
208 int have_ssh1_key;
209 int have_ssh2_key;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000210 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000211} sensitive_data;
212
Damien Miller5428f641999-11-25 11:54:57 +1100213/*
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000214 * Flag indicating whether the RSA server key needs to be regenerated.
215 * Is set in the SIGALRM handler and cleared when the key is regenerated.
Damien Miller5428f641999-11-25 11:54:57 +1100216 */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000217static volatile sig_atomic_t key_do_regen = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000218
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000219/* This is set to true when a signal is received. */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000220static volatile sig_atomic_t received_sighup = 0;
221static volatile sig_atomic_t received_sigterm = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000222
Damien Millerb38eff82000-04-01 11:09:21 +1000223/* session identifier, used by RSA-auth */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000224u_char session_id[16];
Damien Millerb38eff82000-04-01 11:09:21 +1000225
Damien Millereba71ba2000-04-29 23:57:08 +1000226/* same for ssh2 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000227u_char *session_id2 = NULL;
Darren Tucker502d3842003-06-28 12:38:01 +1000228u_int session_id2_len = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000229
Damien Miller942da032000-08-18 13:59:06 +1000230/* record remote hostname or ip */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000231u_int utmp_len = MAXHOSTNAMELEN;
Damien Miller942da032000-08-18 13:59:06 +1000232
Ben Lindstromd84df982001-12-06 16:35:40 +0000233/* options.max_startup sized array of fd ints */
234int *startup_pipes = NULL;
235int startup_pipe; /* in child */
236
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000237/* variables used for privilege separation */
Darren Tucker45150472006-07-12 22:34:17 +1000238int use_privsep = -1;
Darren Tuckera8be9e22004-02-06 16:40:27 +1100239struct monitor *pmonitor = NULL;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000240
Darren Tucker3e33cec2003-10-02 16:12:36 +1000241/* global authentication context */
242Authctxt *the_authctxt = NULL;
243
Darren Tucker45150472006-07-12 22:34:17 +1000244/* sshd_config buffer */
245Buffer cfg;
246
Darren Tucker09991742004-07-17 17:05:14 +1000247/* message to be displayed after login */
248Buffer loginmsg;
249
Damien Miller6433df02006-09-07 10:36:43 +1000250/* Unprivileged user */
251struct passwd *privsep_pw = NULL;
252
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000253/* Prototypes for various functions defined later in this file. */
Ben Lindstrombba81212001-06-25 05:01:22 +0000254void destroy_sensitive_data(void);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000255void demote_sensitive_data(void);
Damien Miller98c7ad62000-03-09 21:27:49 +1100256
Ben Lindstrombba81212001-06-25 05:01:22 +0000257static void do_ssh1_kex(void);
258static void do_ssh2_kex(void);
Damien Miller874d77b2000-10-14 16:23:11 +1100259
Damien Miller98c7ad62000-03-09 21:27:49 +1100260/*
Damien Miller34132e52000-01-14 15:45:46 +1100261 * Close all listening sockets
262 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000263static void
Damien Miller34132e52000-01-14 15:45:46 +1100264close_listen_socks(void)
265{
266 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000267
Damien Miller34132e52000-01-14 15:45:46 +1100268 for (i = 0; i < num_listen_socks; i++)
269 close(listen_socks[i]);
270 num_listen_socks = -1;
271}
272
Ben Lindstromd84df982001-12-06 16:35:40 +0000273static void
274close_startup_pipes(void)
275{
276 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000277
Ben Lindstromd84df982001-12-06 16:35:40 +0000278 if (startup_pipes)
279 for (i = 0; i < options.max_startups; i++)
280 if (startup_pipes[i] != -1)
281 close(startup_pipes[i]);
282}
283
Damien Miller34132e52000-01-14 15:45:46 +1100284/*
Damien Miller95def091999-11-25 00:26:21 +1100285 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
286 * the effect is to reread the configuration file (and to regenerate
287 * the server key).
288 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100289
290/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000291static void
Damien Miller95def091999-11-25 00:26:21 +1100292sighup_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000293{
Ben Lindstrom07958482001-12-06 16:19:01 +0000294 int save_errno = errno;
295
Damien Miller95def091999-11-25 00:26:21 +1100296 received_sighup = 1;
297 signal(SIGHUP, sighup_handler);
Ben Lindstrom07958482001-12-06 16:19:01 +0000298 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000299}
300
Damien Miller95def091999-11-25 00:26:21 +1100301/*
302 * Called from the main program after receiving SIGHUP.
303 * Restarts the server.
304 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000305static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000306sighup_restart(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000307{
Damien Miller996acd22003-04-09 20:59:48 +1000308 logit("Received SIGHUP; restarting.");
Damien Miller34132e52000-01-14 15:45:46 +1100309 close_listen_socks();
Ben Lindstromd84df982001-12-06 16:35:40 +0000310 close_startup_pipes();
Darren Tuckered623962007-02-25 20:37:21 +1100311 alarm(0); /* alarm timer persists across exec */
Darren Tucker2c671bf2010-01-09 22:28:43 +1100312 signal(SIGHUP, SIG_IGN); /* will be restored after exec */
Damien Miller95def091999-11-25 00:26:21 +1100313 execv(saved_argv[0], saved_argv);
Damien Miller996acd22003-04-09 20:59:48 +1000314 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
Ben Lindstrom822b6342002-06-23 21:38:49 +0000315 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100316 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000317}
318
Damien Miller95def091999-11-25 00:26:21 +1100319/*
320 * Generic signal handler for terminating signals in the master daemon.
Damien Miller95def091999-11-25 00:26:21 +1100321 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100322/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000323static void
Damien Miller95def091999-11-25 00:26:21 +1100324sigterm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000325{
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000326 received_sigterm = sig;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000327}
328
Damien Miller95def091999-11-25 00:26:21 +1100329/*
330 * SIGCHLD handler. This is called whenever a child dies. This will then
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000331 * reap any zombies left by exited children.
Damien Miller95def091999-11-25 00:26:21 +1100332 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100333/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000334static void
Damien Miller95def091999-11-25 00:26:21 +1100335main_sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000336{
Damien Miller95def091999-11-25 00:26:21 +1100337 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000338 pid_t pid;
Damien Miller95def091999-11-25 00:26:21 +1100339 int status;
Damien Miller431f66b1999-11-21 18:31:57 +1100340
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000341 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
342 (pid < 0 && errno == EINTR))
Damien Miller95def091999-11-25 00:26:21 +1100343 ;
Damien Miller431f66b1999-11-21 18:31:57 +1100344
Damien Miller95def091999-11-25 00:26:21 +1100345 signal(SIGCHLD, main_sigchld_handler);
346 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000347}
348
Damien Miller95def091999-11-25 00:26:21 +1100349/*
350 * Signal handler for the alarm after the login grace period has expired.
351 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100352/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000353static void
Damien Miller95def091999-11-25 00:26:21 +1100354grace_alarm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000355{
Darren Tuckera8be9e22004-02-06 16:40:27 +1100356 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
357 kill(pmonitor->m_pid, SIGALRM);
358
Damien Miller95def091999-11-25 00:26:21 +1100359 /* Log error and exit. */
Damien Miller99a648e2006-08-19 00:32:20 +1000360 sigdie("Timeout before authentication for %s", get_remote_ipaddr());
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000361}
362
Damien Miller95def091999-11-25 00:26:21 +1100363/*
Damien Miller95def091999-11-25 00:26:21 +1100364 * Signal handler for the key regeneration alarm. Note that this
365 * alarm only occurs in the daemon waiting for connections, and it does not
366 * do anything with the private key or random state before forking.
367 * Thus there should be no concurrency control/asynchronous execution
368 * problems.
369 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000370static void
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000371generate_ephemeral_server_key(void)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100372{
Ben Lindstroma3700052001-04-05 23:26:32 +0000373 verbose("Generating %s%d bit RSA key.",
Damien Millerff75ac42001-03-30 10:50:32 +1000374 sensitive_data.server_key ? "new " : "", options.server_key_bits);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100375 if (sensitive_data.server_key != NULL)
376 key_free(sensitive_data.server_key);
Ben Lindstroma3700052001-04-05 23:26:32 +0000377 sensitive_data.server_key = key_generate(KEY_RSA1,
Damien Millerff75ac42001-03-30 10:50:32 +1000378 options.server_key_bits);
379 verbose("RSA key generation complete.");
Ben Lindstromeb648a72001-03-05 06:00:29 +0000380
Damien Miller354c48c2008-05-19 14:50:00 +1000381 arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
Ben Lindstromeb648a72001-03-05 06:00:29 +0000382 arc4random_stir();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100383}
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000384
Damien Millerf0b15df2006-03-26 13:59:20 +1100385/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000386static void
Damien Miller95def091999-11-25 00:26:21 +1100387key_regeneration_alarm(int sig)
388{
389 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000390
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000391 signal(SIGALRM, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +1100392 errno = save_errno;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000393 key_do_regen = 1;
Damien Miller95def091999-11-25 00:26:21 +1100394}
395
Ben Lindstrombba81212001-06-25 05:01:22 +0000396static void
Damien Millerb38eff82000-04-01 11:09:21 +1000397sshd_exchange_identification(int sock_in, int sock_out)
398{
Damien Millereccb9de2005-06-17 12:59:34 +1000399 u_int i;
400 int mismatch;
Damien Millerb38eff82000-04-01 11:09:21 +1000401 int remote_major, remote_minor;
Damien Miller78928792000-04-12 20:17:38 +1000402 int major, minor;
Darren Tuckerd7bdc0c2008-07-02 22:34:30 +1000403 char *s, *newline = "\n";
Damien Millerb38eff82000-04-01 11:09:21 +1000404 char buf[256]; /* Must not be larger than remote_version. */
405 char remote_version[256]; /* Must be at least as big as buf. */
406
Damien Miller78928792000-04-12 20:17:38 +1000407 if ((options.protocol & SSH_PROTO_1) &&
408 (options.protocol & SSH_PROTO_2)) {
409 major = PROTOCOL_MAJOR_1;
410 minor = 99;
411 } else if (options.protocol & SSH_PROTO_2) {
412 major = PROTOCOL_MAJOR_2;
413 minor = PROTOCOL_MINOR_2;
Darren Tuckerd7bdc0c2008-07-02 22:34:30 +1000414 newline = "\r\n";
Damien Miller78928792000-04-12 20:17:38 +1000415 } else {
416 major = PROTOCOL_MAJOR_1;
417 minor = PROTOCOL_MINOR_1;
418 }
Darren Tuckerd7bdc0c2008-07-02 22:34:30 +1000419 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", major, minor,
420 SSH_VERSION, newline);
Damien Millerb38eff82000-04-01 11:09:21 +1000421 server_version_string = xstrdup(buf);
422
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000423 /* Send our protocol version identification. */
Darren Tuckerc5564e12009-06-21 18:53:53 +1000424 if (roaming_atomicio(vwrite, sock_out, server_version_string,
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000425 strlen(server_version_string))
426 != strlen(server_version_string)) {
427 logit("Could not write ident string to %s", get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000428 cleanup_exit(255);
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000429 }
430
431 /* Read other sides version identification. */
432 memset(buf, 0, sizeof(buf));
433 for (i = 0; i < sizeof(buf) - 1; i++) {
Darren Tuckerc5564e12009-06-21 18:53:53 +1000434 if (roaming_atomicio(read, sock_in, &buf[i], 1) != 1) {
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000435 logit("Did not receive identification string from %s",
436 get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000437 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000438 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000439 if (buf[i] == '\r') {
440 buf[i] = 0;
441 /* Kludge for F-Secure Macintosh < 1.0.2 */
442 if (i == 12 &&
443 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
Damien Millerb38eff82000-04-01 11:09:21 +1000444 break;
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000445 continue;
Damien Millerb38eff82000-04-01 11:09:21 +1000446 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000447 if (buf[i] == '\n') {
448 buf[i] = 0;
449 break;
450 }
Damien Millerb38eff82000-04-01 11:09:21 +1000451 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000452 buf[sizeof(buf) - 1] = 0;
453 client_version_string = xstrdup(buf);
Damien Millerb38eff82000-04-01 11:09:21 +1000454
455 /*
456 * Check that the versions match. In future this might accept
457 * several versions and set appropriate flags to handle them.
458 */
459 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
460 &remote_major, &remote_minor, remote_version) != 3) {
Damien Miller4af51302000-04-16 11:18:38 +1000461 s = "Protocol mismatch.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000462 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Millerb38eff82000-04-01 11:09:21 +1000463 close(sock_in);
464 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000465 logit("Bad protocol version identification '%.100s' from %s",
Damien Millerb38eff82000-04-01 11:09:21 +1000466 client_version_string, get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000467 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000468 }
469 debug("Client protocol version %d.%d; client software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100470 remote_major, remote_minor, remote_version);
Damien Millerb38eff82000-04-01 11:09:21 +1000471
Damien Millerefb4afe2000-04-12 18:45:05 +1000472 compat_datafellows(remote_version);
473
Damien Millere9264972002-09-30 11:59:21 +1000474 if (datafellows & SSH_BUG_PROBE) {
Damien Miller996acd22003-04-09 20:59:48 +1000475 logit("probed from %s with %s. Don't panic.",
Damien Millere9264972002-09-30 11:59:21 +1000476 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000477 cleanup_exit(255);
Damien Millere9264972002-09-30 11:59:21 +1000478 }
479
Damien Miller27dbe6f2001-03-19 22:36:20 +1100480 if (datafellows & SSH_BUG_SCANNER) {
Damien Miller996acd22003-04-09 20:59:48 +1000481 logit("scanned from %s with %s. Don't panic.",
Damien Miller27dbe6f2001-03-19 22:36:20 +1100482 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000483 cleanup_exit(255);
Damien Miller27dbe6f2001-03-19 22:36:20 +1100484 }
485
Damien Miller78928792000-04-12 20:17:38 +1000486 mismatch = 0;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000487 switch (remote_major) {
Damien Millerb38eff82000-04-01 11:09:21 +1000488 case 1:
Damien Millereba71ba2000-04-29 23:57:08 +1000489 if (remote_minor == 99) {
490 if (options.protocol & SSH_PROTO_2)
491 enable_compat20();
492 else
493 mismatch = 1;
494 break;
495 }
Damien Miller78928792000-04-12 20:17:38 +1000496 if (!(options.protocol & SSH_PROTO_1)) {
497 mismatch = 1;
498 break;
499 }
Damien Millerb38eff82000-04-01 11:09:21 +1000500 if (remote_minor < 3) {
Damien Miller37023962000-07-11 17:31:38 +1000501 packet_disconnect("Your ssh version is too old and "
Damien Millerb38eff82000-04-01 11:09:21 +1000502 "is no longer supported. Please install a newer version.");
503 } else if (remote_minor == 3) {
504 /* note that this disables agent-forwarding */
505 enable_compat13();
506 }
Damien Miller78928792000-04-12 20:17:38 +1000507 break;
Damien Millerefb4afe2000-04-12 18:45:05 +1000508 case 2:
Damien Miller78928792000-04-12 20:17:38 +1000509 if (options.protocol & SSH_PROTO_2) {
Damien Millerefb4afe2000-04-12 18:45:05 +1000510 enable_compat20();
511 break;
512 }
513 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000514 default:
Damien Miller78928792000-04-12 20:17:38 +1000515 mismatch = 1;
Damien Millerb38eff82000-04-01 11:09:21 +1000516 break;
517 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000518 chop(server_version_string);
Damien Miller78928792000-04-12 20:17:38 +1000519 debug("Local version string %.200s", server_version_string);
520
521 if (mismatch) {
522 s = "Protocol major versions differ.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000523 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Miller78928792000-04-12 20:17:38 +1000524 close(sock_in);
525 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000526 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
Damien Miller78928792000-04-12 20:17:38 +1000527 get_remote_ipaddr(),
528 server_version_string, client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000529 cleanup_exit(255);
Damien Miller78928792000-04-12 20:17:38 +1000530 }
Damien Millereba71ba2000-04-29 23:57:08 +1000531}
532
Damien Miller0bc1bd82000-11-13 22:57:25 +1100533/* Destroy the host and server keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +1000534void
535destroy_sensitive_data(void)
536{
Damien Miller0bc1bd82000-11-13 22:57:25 +1100537 int i;
538
539 if (sensitive_data.server_key) {
540 key_free(sensitive_data.server_key);
541 sensitive_data.server_key = NULL;
542 }
Damien Miller9f0f5c62001-12-21 14:45:46 +1100543 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100544 if (sensitive_data.host_keys[i]) {
545 key_free(sensitive_data.host_keys[i]);
546 sensitive_data.host_keys[i] = NULL;
547 }
548 }
549 sensitive_data.ssh1_host_key = NULL;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000550 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100551}
Damien Miller0bc1bd82000-11-13 22:57:25 +1100552
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000553/* Demote private to public keys for network child */
554void
555demote_sensitive_data(void)
556{
557 Key *tmp;
558 int i;
559
560 if (sensitive_data.server_key) {
561 tmp = key_demote(sensitive_data.server_key);
562 key_free(sensitive_data.server_key);
563 sensitive_data.server_key = tmp;
564 }
565
566 for (i = 0; i < options.num_host_key_files; i++) {
567 if (sensitive_data.host_keys[i]) {
568 tmp = key_demote(sensitive_data.host_keys[i]);
569 key_free(sensitive_data.host_keys[i]);
570 sensitive_data.host_keys[i] = tmp;
571 if (tmp->type == KEY_RSA1)
572 sensitive_data.ssh1_host_key = tmp;
573 }
574 }
575
576 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
577}
578
Ben Lindstrom08105192002-03-22 02:50:06 +0000579static void
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000580privsep_preauth_child(void)
581{
Darren Tucker64cee362009-06-21 20:26:17 +1000582 u_int32_t rnd[256];
Ben Lindstrom810af962002-07-04 00:11:40 +0000583 gid_t gidset[1];
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000584
585 /* Enable challenge-response authentication for privilege separation */
586 privsep_challenge_enable();
587
Damien Miller76e95da2008-03-07 18:31:24 +1100588 arc4random_stir();
Damien Miller354c48c2008-05-19 14:50:00 +1000589 arc4random_buf(rnd, sizeof(rnd));
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000590 RAND_seed(rnd, sizeof(rnd));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000591
592 /* Demote the private keys to public keys. */
593 demote_sensitive_data();
594
Ben Lindstroma962c2f2002-07-04 00:14:17 +0000595 /* Change our root directory */
Ben Lindstrom7a7edf72002-03-22 02:42:37 +0000596 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
597 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
598 strerror(errno));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000599 if (chdir("/") == -1)
Ben Lindstrom1ee9ec32002-03-22 03:14:45 +0000600 fatal("chdir(\"/\"): %s", strerror(errno));
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000601
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000602 /* Drop our privileges */
Damien Miller6433df02006-09-07 10:36:43 +1000603 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid,
604 (u_int)privsep_pw->pw_gid);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000605#if 0
Darren Tuckerd5920482004-02-29 20:11:30 +1100606 /* XXX not ready, too heavy after chroot */
Damien Miller6433df02006-09-07 10:36:43 +1000607 do_setusercontext(privsep_pw);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000608#else
Damien Miller6433df02006-09-07 10:36:43 +1000609 gidset[0] = privsep_pw->pw_gid;
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000610 if (setgroups(1, gidset) < 0)
611 fatal("setgroups: %.100s", strerror(errno));
Damien Miller6433df02006-09-07 10:36:43 +1000612 permanently_set_uid(privsep_pw);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000613#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000614}
615
Darren Tucker3e33cec2003-10-02 16:12:36 +1000616static int
617privsep_preauth(Authctxt *authctxt)
Ben Lindstrom943481c2002-03-22 03:43:46 +0000618{
Ben Lindstrom943481c2002-03-22 03:43:46 +0000619 int status;
620 pid_t pid;
621
622 /* Set up unprivileged child process to deal with network data */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000623 pmonitor = monitor_init();
Ben Lindstrom943481c2002-03-22 03:43:46 +0000624 /* Store a pointer to the kex for later rekeying */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000625 pmonitor->m_pkex = &xxx_kex;
Ben Lindstrom943481c2002-03-22 03:43:46 +0000626
627 pid = fork();
628 if (pid == -1) {
629 fatal("fork of unprivileged child failed");
630 } else if (pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000631 debug2("Network child is on pid %ld", (long)pid);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000632
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000633 close(pmonitor->m_recvfd);
Darren Tuckera8be9e22004-02-06 16:40:27 +1100634 pmonitor->m_pid = pid;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000635 monitor_child_preauth(authctxt, pmonitor);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000636 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000637
638 /* Sync memory */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000639 monitor_sync(pmonitor);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000640
641 /* Wait for the child's exit status */
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000642 while (waitpid(pid, &status, 0) < 0)
643 if (errno != EINTR)
644 break;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000645 return (1);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000646 } else {
647 /* child */
648
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000649 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000650
651 /* Demote the child */
652 if (getuid() == 0 || geteuid() == 0)
653 privsep_preauth_child();
Ben Lindstromf90f58d2002-03-26 01:53:03 +0000654 setproctitle("%s", "[net]");
Ben Lindstrom943481c2002-03-22 03:43:46 +0000655 }
Darren Tucker3e33cec2003-10-02 16:12:36 +1000656 return (0);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000657}
658
Ben Lindstrom08105192002-03-22 02:50:06 +0000659static void
Ben Lindstrom943481c2002-03-22 03:43:46 +0000660privsep_postauth(Authctxt *authctxt)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000661{
Damien Miller76e95da2008-03-07 18:31:24 +1100662 u_int32_t rnd[256];
Damien Miller76e95da2008-03-07 18:31:24 +1100663
Tim Rice9dd30812002-07-07 13:43:36 -0700664#ifdef DISABLE_FD_PASSING
Tim Rice8eff3192002-06-25 15:35:15 -0700665 if (1) {
666#else
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000667 if (authctxt->pw->pw_uid == 0 || options.use_login) {
Tim Rice8eff3192002-06-25 15:35:15 -0700668#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000669 /* File descriptor passing is broken or root login */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000670 use_privsep = 0;
Darren Tucker45b01422005-10-03 18:20:00 +1000671 goto skip;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000672 }
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000673
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000674 /* New socket pair */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000675 monitor_reinit(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000676
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000677 pmonitor->m_pid = fork();
678 if (pmonitor->m_pid == -1)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000679 fatal("fork of unprivileged child failed");
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000680 else if (pmonitor->m_pid != 0) {
Damien Millerb61f3fc2008-07-11 17:36:48 +1000681 verbose("User child is on pid %ld", (long)pmonitor->m_pid);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000682 close(pmonitor->m_recvfd);
Darren Tuckereb578622004-08-12 23:08:14 +1000683 buffer_clear(&loginmsg);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000684 monitor_child_postauth(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000685
686 /* NEVERREACHED */
687 exit(0);
688 }
689
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000690 close(pmonitor->m_sendfd);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000691
692 /* Demote the private keys to public keys. */
693 demote_sensitive_data();
694
Damien Miller76e95da2008-03-07 18:31:24 +1100695 arc4random_stir();
Damien Miller354c48c2008-05-19 14:50:00 +1000696 arc4random_buf(rnd, sizeof(rnd));
Damien Miller76e95da2008-03-07 18:31:24 +1100697 RAND_seed(rnd, sizeof(rnd));
698
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000699 /* Drop privileges */
700 do_setusercontext(authctxt->pw);
701
Darren Tucker45b01422005-10-03 18:20:00 +1000702 skip:
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000703 /* It is safe now to apply the key state */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000704 monitor_apply_keystate(pmonitor);
Damien Miller9786e6e2005-07-26 21:54:56 +1000705
706 /*
707 * Tell the packet layer that authentication was successful, since
708 * this information is not part of the key state.
709 */
710 packet_set_authenticated();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000711}
712
Ben Lindstrombba81212001-06-25 05:01:22 +0000713static char *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100714list_hostkey_types(void)
715{
Damien Miller0e3b8722002-01-22 23:26:38 +1100716 Buffer b;
Damien Millerf58b58c2003-11-17 21:18:23 +1100717 const char *p;
718 char *ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100719 int i;
Damien Miller0e3b8722002-01-22 23:26:38 +1100720
721 buffer_init(&b);
Damien Miller9f0f5c62001-12-21 14:45:46 +1100722 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100723 Key *key = sensitive_data.host_keys[i];
724 if (key == NULL)
725 continue;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000726 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100727 case KEY_RSA:
728 case KEY_DSA:
Damien Miller0e3b8722002-01-22 23:26:38 +1100729 if (buffer_len(&b) > 0)
730 buffer_append(&b, ",", 1);
731 p = key_ssh_name(key);
732 buffer_append(&b, p, strlen(p));
Damien Miller0bc1bd82000-11-13 22:57:25 +1100733 break;
734 }
735 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100736 buffer_append(&b, "\0", 1);
Damien Millerf58b58c2003-11-17 21:18:23 +1100737 ret = xstrdup(buffer_ptr(&b));
Damien Miller0e3b8722002-01-22 23:26:38 +1100738 buffer_free(&b);
Damien Millerf58b58c2003-11-17 21:18:23 +1100739 debug("list_hostkey_types: %s", ret);
740 return ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100741}
742
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000743Key *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100744get_hostkey_by_type(int type)
745{
746 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000747
Damien Miller9f0f5c62001-12-21 14:45:46 +1100748 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100749 Key *key = sensitive_data.host_keys[i];
750 if (key != NULL && key->type == type)
751 return key;
752 }
753 return NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000754}
755
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000756Key *
757get_hostkey_by_index(int ind)
758{
759 if (ind < 0 || ind >= options.num_host_key_files)
760 return (NULL);
761 return (sensitive_data.host_keys[ind]);
762}
763
764int
765get_hostkey_index(Key *key)
766{
767 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000768
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000769 for (i = 0; i < options.num_host_key_files; i++) {
770 if (key == sensitive_data.host_keys[i])
771 return (i);
772 }
773 return (-1);
774}
775
Damien Miller942da032000-08-18 13:59:06 +1000776/*
777 * returns 1 if connection should be dropped, 0 otherwise.
778 * dropping starts at connection #max_startups_begin with a probability
779 * of (max_startups_rate/100). the probability increases linearly until
780 * all connections are dropped for startups > max_startups
781 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000782static int
Damien Miller942da032000-08-18 13:59:06 +1000783drop_connection(int startups)
784{
Darren Tucker178fa662004-11-05 20:09:09 +1100785 int p, r;
Damien Miller942da032000-08-18 13:59:06 +1000786
787 if (startups < options.max_startups_begin)
788 return 0;
789 if (startups >= options.max_startups)
790 return 1;
791 if (options.max_startups_rate == 100)
792 return 1;
793
794 p = 100 - options.max_startups_rate;
795 p *= startups - options.max_startups_begin;
Darren Tucker178fa662004-11-05 20:09:09 +1100796 p /= options.max_startups - options.max_startups_begin;
Damien Miller942da032000-08-18 13:59:06 +1000797 p += options.max_startups_rate;
Damien Miller354c48c2008-05-19 14:50:00 +1000798 r = arc4random_uniform(100);
Damien Miller942da032000-08-18 13:59:06 +1000799
Darren Tucker3269b132004-11-05 20:20:59 +1100800 debug("drop_connection: p %d, r %d", p, r);
Damien Miller942da032000-08-18 13:59:06 +1000801 return (r < p) ? 1 : 0;
802}
803
Ben Lindstromade03f62001-12-06 18:22:17 +0000804static void
805usage(void)
806{
Damien Miller0c889cd2004-03-22 09:36:00 +1100807 fprintf(stderr, "%s, %s\n",
Damien Miller2aa6d3c2004-09-12 16:53:04 +1000808 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
Damien Millerb4087862004-03-22 09:35:21 +1100809 fprintf(stderr,
Darren Tuckere7f3f752008-06-10 23:06:01 +1000810"usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-f config_file]\n"
811" [-g login_grace_time] [-h host_key_file] [-k key_gen_time]\n"
812" [-o option] [-p port] [-u len]\n"
Damien Millerb4087862004-03-22 09:35:21 +1100813 );
Ben Lindstromade03f62001-12-06 18:22:17 +0000814 exit(1);
815}
816
Darren Tucker645ab752004-06-25 13:33:20 +1000817static void
818send_rexec_state(int fd, Buffer *conf)
819{
820 Buffer m;
821
822 debug3("%s: entering fd = %d config len %d", __func__, fd,
823 buffer_len(conf));
824
825 /*
826 * Protocol from reexec master to child:
827 * string configuration
828 * u_int ephemeral_key_follows
829 * bignum e (only if ephemeral_key_follows == 1)
830 * bignum n "
831 * bignum d "
832 * bignum iqmp "
833 * bignum p "
834 * bignum q "
Darren Tuckerc6f82192005-09-27 22:46:32 +1000835 * string rngseed (only if OpenSSL is not self-seeded)
Darren Tucker645ab752004-06-25 13:33:20 +1000836 */
837 buffer_init(&m);
838 buffer_put_cstring(&m, buffer_ptr(conf));
839
Darren Tuckerfc959702004-07-17 16:12:08 +1000840 if (sensitive_data.server_key != NULL &&
Darren Tucker645ab752004-06-25 13:33:20 +1000841 sensitive_data.server_key->type == KEY_RSA1) {
842 buffer_put_int(&m, 1);
843 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
844 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
845 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
846 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
847 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
848 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
849 } else
850 buffer_put_int(&m, 0);
851
Darren Tuckerc6f82192005-09-27 22:46:32 +1000852#ifndef OPENSSL_PRNG_ONLY
853 rexec_send_rng_seed(&m);
854#endif
855
Darren Tucker645ab752004-06-25 13:33:20 +1000856 if (ssh_msg_send(fd, 0, &m) == -1)
857 fatal("%s: ssh_msg_send failed", __func__);
858
859 buffer_free(&m);
860
861 debug3("%s: done", __func__);
862}
863
864static void
865recv_rexec_state(int fd, Buffer *conf)
866{
867 Buffer m;
868 char *cp;
869 u_int len;
870
871 debug3("%s: entering fd = %d", __func__, fd);
872
873 buffer_init(&m);
874
875 if (ssh_msg_recv(fd, &m) == -1)
876 fatal("%s: ssh_msg_recv failed", __func__);
877 if (buffer_get_char(&m) != 0)
878 fatal("%s: rexec version mismatch", __func__);
879
880 cp = buffer_get_string(&m, &len);
881 if (conf != NULL)
882 buffer_append(conf, cp, len + 1);
883 xfree(cp);
884
885 if (buffer_get_int(&m)) {
886 if (sensitive_data.server_key != NULL)
887 key_free(sensitive_data.server_key);
888 sensitive_data.server_key = key_new_private(KEY_RSA1);
889 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
890 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
891 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
892 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
893 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
894 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
895 rsa_generate_additional_parameters(
896 sensitive_data.server_key->rsa);
897 }
Darren Tuckerc6f82192005-09-27 22:46:32 +1000898
899#ifndef OPENSSL_PRNG_ONLY
900 rexec_recv_rng_seed(&m);
901#endif
902
Darren Tucker645ab752004-06-25 13:33:20 +1000903 buffer_free(&m);
904
905 debug3("%s: done", __func__);
906}
907
Damien Millera1f68402006-08-19 00:31:39 +1000908/* Accept a connection from inetd */
909static void
910server_accept_inetd(int *sock_in, int *sock_out)
911{
912 int fd;
913
914 startup_pipe = -1;
915 if (rexeced_flag) {
916 close(REEXEC_CONFIG_PASS_FD);
917 *sock_in = *sock_out = dup(STDIN_FILENO);
918 if (!debug_flag) {
919 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
920 close(REEXEC_STARTUP_PIPE_FD);
921 }
922 } else {
923 *sock_in = dup(STDIN_FILENO);
924 *sock_out = dup(STDOUT_FILENO);
925 }
926 /*
927 * We intentionally do not close the descriptors 0, 1, and 2
928 * as our code for setting the descriptors won't work if
929 * ttyfd happens to be one of those.
930 */
931 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
932 dup2(fd, STDIN_FILENO);
933 dup2(fd, STDOUT_FILENO);
934 if (fd > STDOUT_FILENO)
935 close(fd);
936 }
937 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
938}
939
940/*
941 * Listen for TCP connections
942 */
943static void
944server_listen(void)
945{
946 int ret, listen_sock, on = 1;
947 struct addrinfo *ai;
948 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
949
950 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
951 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
952 continue;
953 if (num_listen_socks >= MAX_LISTEN_SOCKS)
954 fatal("Too many listen sockets. "
955 "Enlarge MAX_LISTEN_SOCKS");
956 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
957 ntop, sizeof(ntop), strport, sizeof(strport),
958 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
959 error("getnameinfo failed: %.100s",
Darren Tucker4abde772007-12-29 02:43:51 +1100960 ssh_gai_strerror(ret));
Damien Millera1f68402006-08-19 00:31:39 +1000961 continue;
962 }
963 /* Create socket for listening. */
Darren Tucker7bd98e72010-01-10 10:31:12 +1100964 listen_sock = socket(ai->ai_family, ai->ai_socktype,
965 ai->ai_protocol);
Damien Millera1f68402006-08-19 00:31:39 +1000966 if (listen_sock < 0) {
967 /* kernel may not support ipv6 */
968 verbose("socket: %.100s", strerror(errno));
969 continue;
970 }
971 if (set_nonblock(listen_sock) == -1) {
972 close(listen_sock);
973 continue;
974 }
975 /*
976 * Set socket options.
977 * Allow local port reuse in TIME_WAIT.
978 */
979 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
980 &on, sizeof(on)) == -1)
981 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
982
Damien Miller49d2a282008-01-20 08:56:00 +1100983 /* Only communicate in IPv6 over AF_INET6 sockets. */
Damien Miller04ee0f82009-11-18 17:48:30 +1100984 if (ai->ai_family == AF_INET6)
985 sock_set_v6only(listen_sock);
Damien Miller49d2a282008-01-20 08:56:00 +1100986
Damien Millera1f68402006-08-19 00:31:39 +1000987 debug("Bind to port %s on %s.", strport, ntop);
988
989 /* Bind the socket to the desired port. */
990 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
991 error("Bind to port %s on %s failed: %.200s.",
992 strport, ntop, strerror(errno));
993 close(listen_sock);
994 continue;
995 }
996 listen_socks[num_listen_socks] = listen_sock;
997 num_listen_socks++;
998
999 /* Start listening on the port. */
1000 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1001 fatal("listen on [%s]:%s: %.100s",
1002 ntop, strport, strerror(errno));
1003 logit("Server listening on %s port %s.", ntop, strport);
1004 }
1005 freeaddrinfo(options.listen_addrs);
1006
1007 if (!num_listen_socks)
1008 fatal("Cannot bind any address.");
1009}
1010
1011/*
1012 * The main TCP accept loop. Note that, for the non-debug case, returns
1013 * from this function are in a forked subprocess.
1014 */
1015static void
1016server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1017{
1018 fd_set *fdset;
1019 int i, j, ret, maxfd;
1020 int key_used = 0, startups = 0;
1021 int startup_p[2] = { -1 , -1 };
1022 struct sockaddr_storage from;
1023 socklen_t fromlen;
1024 pid_t pid;
1025
1026 /* setup fd set for accept */
1027 fdset = NULL;
1028 maxfd = 0;
1029 for (i = 0; i < num_listen_socks; i++)
1030 if (listen_socks[i] > maxfd)
1031 maxfd = listen_socks[i];
1032 /* pipes connected to unauthenticated childs */
1033 startup_pipes = xcalloc(options.max_startups, sizeof(int));
1034 for (i = 0; i < options.max_startups; i++)
1035 startup_pipes[i] = -1;
1036
1037 /*
1038 * Stay listening for connections until the system crashes or
1039 * the daemon is killed with a signal.
1040 */
1041 for (;;) {
1042 if (received_sighup)
1043 sighup_restart();
1044 if (fdset != NULL)
1045 xfree(fdset);
1046 fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS),
1047 sizeof(fd_mask));
1048
1049 for (i = 0; i < num_listen_socks; i++)
1050 FD_SET(listen_socks[i], fdset);
1051 for (i = 0; i < options.max_startups; i++)
1052 if (startup_pipes[i] != -1)
1053 FD_SET(startup_pipes[i], fdset);
1054
1055 /* Wait in select until there is a connection. */
1056 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1057 if (ret < 0 && errno != EINTR)
1058 error("select: %.100s", strerror(errno));
1059 if (received_sigterm) {
1060 logit("Received signal %d; terminating.",
1061 (int) received_sigterm);
1062 close_listen_socks();
1063 unlink(options.pid_file);
1064 exit(255);
1065 }
1066 if (key_used && key_do_regen) {
1067 generate_ephemeral_server_key();
1068 key_used = 0;
1069 key_do_regen = 0;
1070 }
1071 if (ret < 0)
1072 continue;
1073
1074 for (i = 0; i < options.max_startups; i++)
1075 if (startup_pipes[i] != -1 &&
1076 FD_ISSET(startup_pipes[i], fdset)) {
1077 /*
1078 * the read end of the pipe is ready
1079 * if the child has closed the pipe
1080 * after successful authentication
1081 * or if the child has died
1082 */
1083 close(startup_pipes[i]);
1084 startup_pipes[i] = -1;
1085 startups--;
1086 }
1087 for (i = 0; i < num_listen_socks; i++) {
1088 if (!FD_ISSET(listen_socks[i], fdset))
1089 continue;
1090 fromlen = sizeof(from);
1091 *newsock = accept(listen_socks[i],
1092 (struct sockaddr *)&from, &fromlen);
1093 if (*newsock < 0) {
Damien Millerd8968ad2008-07-04 23:10:49 +10001094 if (errno != EINTR && errno != EAGAIN &&
1095 errno != EWOULDBLOCK)
Damien Millera1f68402006-08-19 00:31:39 +10001096 error("accept: %.100s", strerror(errno));
1097 continue;
1098 }
1099 if (unset_nonblock(*newsock) == -1) {
1100 close(*newsock);
1101 continue;
1102 }
1103 if (drop_connection(startups) == 1) {
1104 debug("drop connection #%d", startups);
1105 close(*newsock);
1106 continue;
1107 }
1108 if (pipe(startup_p) == -1) {
1109 close(*newsock);
1110 continue;
1111 }
1112
1113 if (rexec_flag && socketpair(AF_UNIX,
1114 SOCK_STREAM, 0, config_s) == -1) {
1115 error("reexec socketpair: %s",
1116 strerror(errno));
1117 close(*newsock);
1118 close(startup_p[0]);
1119 close(startup_p[1]);
1120 continue;
1121 }
1122
1123 for (j = 0; j < options.max_startups; j++)
1124 if (startup_pipes[j] == -1) {
1125 startup_pipes[j] = startup_p[0];
1126 if (maxfd < startup_p[0])
1127 maxfd = startup_p[0];
1128 startups++;
1129 break;
1130 }
1131
1132 /*
1133 * Got connection. Fork a child to handle it, unless
1134 * we are in debugging mode.
1135 */
1136 if (debug_flag) {
1137 /*
1138 * In debugging mode. Close the listening
1139 * socket, and start processing the
1140 * connection without forking.
1141 */
1142 debug("Server will not fork when running in debugging mode.");
1143 close_listen_socks();
1144 *sock_in = *newsock;
1145 *sock_out = *newsock;
1146 close(startup_p[0]);
1147 close(startup_p[1]);
1148 startup_pipe = -1;
1149 pid = getpid();
1150 if (rexec_flag) {
1151 send_rexec_state(config_s[0],
1152 &cfg);
1153 close(config_s[0]);
1154 }
1155 break;
1156 }
1157
1158 /*
1159 * Normal production daemon. Fork, and have
1160 * the child process the connection. The
1161 * parent continues listening.
1162 */
Damien Miller1b06dc32006-08-31 03:24:41 +10001163 platform_pre_fork();
Damien Millera1f68402006-08-19 00:31:39 +10001164 if ((pid = fork()) == 0) {
1165 /*
1166 * Child. Close the listening and
1167 * max_startup sockets. Start using
1168 * the accepted socket. Reinitialize
1169 * logging (since our pid has changed).
1170 * We break out of the loop to handle
1171 * the connection.
1172 */
Damien Miller1b06dc32006-08-31 03:24:41 +10001173 platform_post_fork_child();
Damien Millera1f68402006-08-19 00:31:39 +10001174 startup_pipe = startup_p[1];
1175 close_startup_pipes();
1176 close_listen_socks();
1177 *sock_in = *newsock;
1178 *sock_out = *newsock;
1179 log_init(__progname,
1180 options.log_level,
1181 options.log_facility,
1182 log_stderr);
1183 if (rexec_flag)
1184 close(config_s[0]);
1185 break;
1186 }
1187
1188 /* Parent. Stay in the loop. */
Damien Miller1b06dc32006-08-31 03:24:41 +10001189 platform_post_fork_parent(pid);
Damien Millera1f68402006-08-19 00:31:39 +10001190 if (pid < 0)
1191 error("fork: %.100s", strerror(errno));
1192 else
1193 debug("Forked child %ld.", (long)pid);
1194
1195 close(startup_p[1]);
1196
1197 if (rexec_flag) {
1198 send_rexec_state(config_s[0], &cfg);
1199 close(config_s[0]);
1200 close(config_s[1]);
1201 }
1202
1203 /*
1204 * Mark that the key has been used (it
1205 * was "given" to the child).
1206 */
1207 if ((options.protocol & SSH_PROTO_1) &&
1208 key_used == 0) {
1209 /* Schedule server key regeneration alarm. */
1210 signal(SIGALRM, key_regeneration_alarm);
1211 alarm(options.key_regeneration_time);
1212 key_used = 1;
1213 }
1214
1215 close(*newsock);
1216
1217 /*
1218 * Ensure that our random state differs
1219 * from that of the child
1220 */
1221 arc4random_stir();
1222 }
1223
1224 /* child process check (or debug mode) */
1225 if (num_listen_socks < 0)
1226 break;
1227 }
1228}
1229
1230
Damien Miller95def091999-11-25 00:26:21 +11001231/*
1232 * Main program for the daemon.
1233 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001234int
1235main(int ac, char **av)
1236{
Damien Miller95def091999-11-25 00:26:21 +11001237 extern char *optarg;
1238 extern int optind;
Damien Millera1f68402006-08-19 00:31:39 +10001239 int opt, i, on = 1;
Damien Miller386c6a22004-06-30 22:40:20 +10001240 int sock_in = -1, sock_out = -1, newsock = -1;
Damien Miller95def091999-11-25 00:26:21 +11001241 const char *remote_ip;
Darren Tuckere7140f22008-06-10 23:01:51 +10001242 char *test_user = NULL, *test_host = NULL, *test_addr = NULL;
Damien Miller95def091999-11-25 00:26:21 +11001243 int remote_port;
Darren Tuckere7140f22008-06-10 23:01:51 +10001244 char *line, *p, *cp;
Damien Millera1f68402006-08-19 00:31:39 +10001245 int config_s[2] = { -1 , -1 };
Damien Millerb61f3fc2008-07-11 17:36:48 +10001246 u_int64_t ibytes, obytes;
Damien Miller6ca16c62008-06-16 07:50:58 +10001247 mode_t new_umask;
Ben Lindstromd0fca422001-03-26 13:44:06 +00001248 Key *key;
Darren Tucker3e33cec2003-10-02 16:12:36 +10001249 Authctxt *authctxt;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001250
Kevin Steves0ea1d9d2002-04-25 18:17:04 +00001251#ifdef HAVE_SECUREWARE
1252 (void)set_auth_parameters(ac, av);
1253#endif
Damien Miller59d3d5b2003-08-22 09:34:41 +10001254 __progname = ssh_get_progname(av[0]);
Damien Millerf9b625c2000-07-09 22:42:32 +10001255 init_rng();
1256
Damien Millera8ed44b2003-01-10 09:53:12 +11001257 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
Damien Millerb8c656e2000-06-28 15:22:41 +10001258 saved_argc = ac;
Darren Tucker17c5d032004-06-25 14:22:23 +10001259 rexec_argc = ac;
Darren Tuckerd8093e42006-05-04 16:24:34 +10001260 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
Damien Millera8ed44b2003-01-10 09:53:12 +11001261 for (i = 0; i < ac; i++)
1262 saved_argv[i] = xstrdup(av[i]);
Damien Miller04cb5362003-05-15 21:29:10 +10001263 saved_argv[i] = NULL;
Damien Millera8ed44b2003-01-10 09:53:12 +11001264
1265#ifndef HAVE_SETPROCTITLE
1266 /* Prepare for later setproctitle emulation */
1267 compat_init_setproctitle(ac, av);
Damien Millerf2e3e9d2003-06-02 12:15:54 +10001268 av = saved_argv;
Damien Millera8ed44b2003-01-10 09:53:12 +11001269#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001270
Damien Millerbfba3542004-03-22 09:29:57 +11001271 if (geteuid() == 0 && setgroups(0, NULL) == -1)
1272 debug("setgroups(): %.200s", strerror(errno));
1273
Darren Tuckerce321d82005-10-03 18:11:24 +10001274 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1275 sanitise_stdfd();
1276
Damien Miller95def091999-11-25 00:26:21 +11001277 /* Initialize configuration options to their default values. */
1278 initialize_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001279
Damien Miller95def091999-11-25 00:26:21 +11001280 /* Parse command-line arguments. */
Darren Tuckere7140f22008-06-10 23:01:51 +10001281 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:C:dDeiqrtQRT46")) != -1) {
Damien Miller95def091999-11-25 00:26:21 +11001282 switch (opt) {
Damien Miller34132e52000-01-14 15:45:46 +11001283 case '4':
Darren Tucker0f383232005-01-20 10:57:56 +11001284 options.address_family = AF_INET;
Damien Miller34132e52000-01-14 15:45:46 +11001285 break;
1286 case '6':
Darren Tucker0f383232005-01-20 10:57:56 +11001287 options.address_family = AF_INET6;
Damien Miller34132e52000-01-14 15:45:46 +11001288 break;
Damien Miller95def091999-11-25 00:26:21 +11001289 case 'f':
1290 config_file_name = optarg;
1291 break;
1292 case 'd':
Darren Tuckere98dfa32003-07-19 19:54:31 +10001293 if (debug_flag == 0) {
Damien Millere4340be2000-09-16 13:29:08 +11001294 debug_flag = 1;
1295 options.log_level = SYSLOG_LEVEL_DEBUG1;
Darren Tuckere98dfa32003-07-19 19:54:31 +10001296 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
Damien Millere4340be2000-09-16 13:29:08 +11001297 options.log_level++;
Damien Miller95def091999-11-25 00:26:21 +11001298 break;
Ben Lindstromc72745a2000-12-02 19:03:54 +00001299 case 'D':
1300 no_daemon_flag = 1;
1301 break;
Ben Lindstrom9fce9f02001-04-11 23:10:09 +00001302 case 'e':
1303 log_stderr = 1;
1304 break;
Damien Miller95def091999-11-25 00:26:21 +11001305 case 'i':
1306 inetd_flag = 1;
1307 break;
Darren Tucker645ab752004-06-25 13:33:20 +10001308 case 'r':
1309 rexec_flag = 0;
1310 break;
1311 case 'R':
1312 rexeced_flag = 1;
1313 inetd_flag = 1;
1314 break;
Damien Miller95def091999-11-25 00:26:21 +11001315 case 'Q':
Ben Lindstromd5390202001-01-29 08:07:43 +00001316 /* ignored */
Damien Miller95def091999-11-25 00:26:21 +11001317 break;
1318 case 'q':
1319 options.log_level = SYSLOG_LEVEL_QUIET;
1320 break;
1321 case 'b':
Damien Millerf0b15df2006-03-26 13:59:20 +11001322 options.server_key_bits = (int)strtonum(optarg, 256,
1323 32768, NULL);
Damien Miller95def091999-11-25 00:26:21 +11001324 break;
1325 case 'p':
Damien Miller34132e52000-01-14 15:45:46 +11001326 options.ports_from_cmdline = 1;
Damien Millere4340be2000-09-16 13:29:08 +11001327 if (options.num_ports >= MAX_PORTS) {
1328 fprintf(stderr, "too many ports.\n");
1329 exit(1);
1330 }
Ben Lindstrom19066a12001-04-12 23:39:26 +00001331 options.ports[options.num_ports++] = a2port(optarg);
Damien Miller3dc71ad2009-01-28 16:31:22 +11001332 if (options.ports[options.num_ports-1] <= 0) {
Ben Lindstrom19066a12001-04-12 23:39:26 +00001333 fprintf(stderr, "Bad port number.\n");
1334 exit(1);
1335 }
Damien Miller95def091999-11-25 00:26:21 +11001336 break;
1337 case 'g':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +00001338 if ((options.login_grace_time = convtime(optarg)) == -1) {
1339 fprintf(stderr, "Invalid login grace time.\n");
1340 exit(1);
1341 }
Damien Miller95def091999-11-25 00:26:21 +11001342 break;
1343 case 'k':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +00001344 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
1345 fprintf(stderr, "Invalid key regeneration interval.\n");
1346 exit(1);
1347 }
Damien Miller95def091999-11-25 00:26:21 +11001348 break;
1349 case 'h':
Damien Miller0bc1bd82000-11-13 22:57:25 +11001350 if (options.num_host_key_files >= MAX_HOSTKEYS) {
1351 fprintf(stderr, "too many host keys.\n");
1352 exit(1);
1353 }
1354 options.host_key_files[options.num_host_key_files++] = optarg;
Damien Miller95def091999-11-25 00:26:21 +11001355 break;
Ben Lindstrom794325a2001-08-06 21:09:07 +00001356 case 't':
1357 test_flag = 1;
1358 break;
Darren Tuckere7140f22008-06-10 23:01:51 +10001359 case 'T':
1360 test_flag = 2;
1361 break;
1362 case 'C':
1363 cp = optarg;
1364 while ((p = strsep(&cp, ",")) && *p != '\0') {
1365 if (strncmp(p, "addr=", 5) == 0)
1366 test_addr = xstrdup(p + 5);
1367 else if (strncmp(p, "host=", 5) == 0)
1368 test_host = xstrdup(p + 5);
1369 else if (strncmp(p, "user=", 5) == 0)
1370 test_user = xstrdup(p + 5);
1371 else {
1372 fprintf(stderr, "Invalid test "
1373 "mode specification %s\n", p);
1374 exit(1);
1375 }
1376 }
1377 break;
Damien Miller942da032000-08-18 13:59:06 +10001378 case 'u':
Damien Millerf0b15df2006-03-26 13:59:20 +11001379 utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL);
Ben Lindstrom41daec72002-07-23 21:15:13 +00001380 if (utmp_len > MAXHOSTNAMELEN) {
1381 fprintf(stderr, "Invalid utmp length.\n");
1382 exit(1);
1383 }
Damien Miller942da032000-08-18 13:59:06 +10001384 break;
Ben Lindstromade03f62001-12-06 18:22:17 +00001385 case 'o':
Damien Millerb9997192003-12-17 16:29:22 +11001386 line = xstrdup(optarg);
1387 if (process_server_config_line(&options, line,
Darren Tucker45150472006-07-12 22:34:17 +10001388 "command-line", 0, NULL, NULL, NULL, NULL) != 0)
Damien Miller9f0f5c62001-12-21 14:45:46 +11001389 exit(1);
Damien Millerb9997192003-12-17 16:29:22 +11001390 xfree(line);
Ben Lindstromade03f62001-12-06 18:22:17 +00001391 break;
Damien Miller95def091999-11-25 00:26:21 +11001392 case '?':
1393 default:
Ben Lindstromade03f62001-12-06 18:22:17 +00001394 usage();
1395 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001396 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001397 }
Darren Tucker645ab752004-06-25 13:33:20 +10001398 if (rexeced_flag || inetd_flag)
1399 rexec_flag = 0;
Damien Miller2ee0c432008-03-07 18:31:47 +11001400 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
Darren Tucker645ab752004-06-25 13:33:20 +10001401 fatal("sshd re-exec requires execution with an absolute path");
1402 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001403 closefrom(REEXEC_MIN_FREE_FD);
1404 else
1405 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001406
Ben Lindstrom425fb022001-03-29 00:31:20 +00001407 SSLeay_add_all_algorithms();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001408
Damien Miller34132e52000-01-14 15:45:46 +11001409 /*
1410 * Force logging to stderr until we have loaded the private host
1411 * key (unless started from inetd)
1412 */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001413 log_init(__progname,
Damien Miller5aa5d782002-02-08 22:01:54 +11001414 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1415 SYSLOG_LEVEL_INFO : options.log_level,
1416 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1417 SYSLOG_FACILITY_AUTH : options.log_facility,
Ben Lindstromc2faa4a2002-11-09 15:50:03 +00001418 log_stderr || !inetd_flag);
Damien Miller34132e52000-01-14 15:45:46 +11001419
Darren Tucker86c093d2004-03-08 22:59:03 +11001420 /*
1421 * Unset KRB5CCNAME, otherwise the user's session may inherit it from
1422 * root's environment
Damien Miller94cf4c82005-07-17 17:04:47 +10001423 */
Darren Tucker9dc6c7d2005-02-02 18:30:33 +11001424 if (getenv("KRB5CCNAME") != NULL)
1425 unsetenv("KRB5CCNAME");
1426
Tim Rice81ed5182002-09-25 17:38:46 -07001427#ifdef _UNICOS
Darren Tucker12984962004-05-24 13:37:13 +10001428 /* Cray can define user privs drop all privs now!
Ben Lindstrom6db66ff2001-08-06 23:29:16 +00001429 * Not needed on PRIV_SU systems!
1430 */
1431 drop_cray_privs();
1432#endif
1433
Darren Tucker645ab752004-06-25 13:33:20 +10001434 sensitive_data.server_key = NULL;
1435 sensitive_data.ssh1_host_key = NULL;
1436 sensitive_data.have_ssh1_key = 0;
1437 sensitive_data.have_ssh2_key = 0;
1438
Darren Tuckere7140f22008-06-10 23:01:51 +10001439 /*
1440 * If we're doing an extended config test, make sure we have all of
1441 * the parameters we need. If we're not doing an extended test,
1442 * do not silently ignore connection test params.
1443 */
Damien Miller2a628472008-06-16 07:50:24 +10001444 if (test_flag >= 2 &&
1445 (test_user != NULL || test_host != NULL || test_addr != NULL)
Darren Tuckere7140f22008-06-10 23:01:51 +10001446 && (test_user == NULL || test_host == NULL || test_addr == NULL))
1447 fatal("user, host and addr are all required when testing "
1448 "Match configs");
1449 if (test_flag < 2 && (test_user != NULL || test_host != NULL ||
1450 test_addr != NULL))
1451 fatal("Config test connection parameter (-C) provided without "
1452 "test mode (-T)");
1453
Darren Tucker645ab752004-06-25 13:33:20 +10001454 /* Fetch our configuration */
1455 buffer_init(&cfg);
1456 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001457 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
Darren Tucker645ab752004-06-25 13:33:20 +10001458 else
1459 load_server_config(config_file_name, &cfg);
1460
Darren Tucker45150472006-07-12 22:34:17 +10001461 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1462 &cfg, NULL, NULL, NULL);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001463
Darren Tuckerc6f82192005-09-27 22:46:32 +10001464 seed_rng();
1465
Damien Miller95def091999-11-25 00:26:21 +11001466 /* Fill in default values for those options not explicitly set. */
1467 fill_default_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001468
Darren Tucker97b1bb52007-03-21 20:38:53 +11001469 /* challenge-response is implemented via keyboard interactive */
1470 if (options.challenge_response_authentication)
1471 options.kbd_interactive_authentication = 1;
1472
Darren Tucker7bd98e72010-01-10 10:31:12 +11001473 /* set default channel AF */
Darren Tucker0f383232005-01-20 10:57:56 +11001474 channel_set_af(options.address_family);
1475
Damien Miller95def091999-11-25 00:26:21 +11001476 /* Check that there are no remaining arguments. */
1477 if (optind < ac) {
1478 fprintf(stderr, "Extra argument %s.\n", av[optind]);
1479 exit(1);
1480 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001481
Damien Miller2aa6d3c2004-09-12 16:53:04 +10001482 debug("sshd version %.100s", SSH_RELEASE);
Damien Miller2ccf6611999-11-15 15:25:10 +11001483
Darren Tuckerdf0e4382006-11-07 11:28:40 +11001484 /* Store privilege separation user for later use if required. */
1485 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
1486 if (use_privsep || options.kerberos_authentication)
1487 fatal("Privilege separation user %s does not exist",
1488 SSH_PRIVSEP_USER);
1489 } else {
1490 memset(privsep_pw->pw_passwd, 0, strlen(privsep_pw->pw_passwd));
1491 privsep_pw = pwcopy(privsep_pw);
1492 xfree(privsep_pw->pw_passwd);
1493 privsep_pw->pw_passwd = xstrdup("*");
1494 }
Damien Miller6433df02006-09-07 10:36:43 +10001495 endpwent();
1496
Damien Miller0bc1bd82000-11-13 22:57:25 +11001497 /* load private host keys */
Damien Miller07d86be2006-03-26 14:19:21 +11001498 sensitive_data.host_keys = xcalloc(options.num_host_key_files,
Ben Lindstroma962c2f2002-07-04 00:14:17 +00001499 sizeof(Key *));
Damien Miller9f0f5c62001-12-21 14:45:46 +11001500 for (i = 0; i < options.num_host_key_files; i++)
Ben Lindstrom46c16222000-12-22 01:43:59 +00001501 sensitive_data.host_keys[i] = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +10001502
Damien Miller9f0f5c62001-12-21 14:45:46 +11001503 for (i = 0; i < options.num_host_key_files; i++) {
Ben Lindstromd0fca422001-03-26 13:44:06 +00001504 key = key_load_private(options.host_key_files[i], "", NULL);
1505 sensitive_data.host_keys[i] = key;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001506 if (key == NULL) {
Ben Lindstrom15f33862001-04-16 02:00:02 +00001507 error("Could not load host key: %s",
1508 options.host_key_files[i]);
Ben Lindstromd0fca422001-03-26 13:44:06 +00001509 sensitive_data.host_keys[i] = NULL;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001510 continue;
1511 }
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +00001512 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +11001513 case KEY_RSA1:
1514 sensitive_data.ssh1_host_key = key;
1515 sensitive_data.have_ssh1_key = 1;
1516 break;
1517 case KEY_RSA:
1518 case KEY_DSA:
1519 sensitive_data.have_ssh2_key = 1;
1520 break;
1521 }
Ben Lindstromd0fca422001-03-26 13:44:06 +00001522 debug("private host key: #%d type %d %s", i, key->type,
1523 key_type(key));
Damien Miller0bc1bd82000-11-13 22:57:25 +11001524 }
1525 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001526 logit("Disabling protocol version 1. Could not load host key");
Damien Millereba71ba2000-04-29 23:57:08 +10001527 options.protocol &= ~SSH_PROTO_1;
1528 }
Damien Miller0bc1bd82000-11-13 22:57:25 +11001529 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001530 logit("Disabling protocol version 2. Could not load host key");
Damien Miller0bc1bd82000-11-13 22:57:25 +11001531 options.protocol &= ~SSH_PROTO_2;
Damien Millereba71ba2000-04-29 23:57:08 +10001532 }
Kevin Stevesadf74cd2001-02-05 14:22:50 +00001533 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
Damien Miller996acd22003-04-09 20:59:48 +10001534 logit("sshd: no hostkeys available -- exiting.");
Damien Miller95def091999-11-25 00:26:21 +11001535 exit(1);
1536 }
Damien Miller95def091999-11-25 00:26:21 +11001537
Damien Millereba71ba2000-04-29 23:57:08 +10001538 /* Check certain values for sanity. */
1539 if (options.protocol & SSH_PROTO_1) {
1540 if (options.server_key_bits < 512 ||
1541 options.server_key_bits > 32768) {
1542 fprintf(stderr, "Bad server key size.\n");
1543 exit(1);
1544 }
1545 /*
1546 * Check that server and host key lengths differ sufficiently. This
1547 * is necessary to make double encryption work with rsaref. Oh, I
1548 * hate software patents. I dont know if this can go? Niels
1549 */
1550 if (options.server_key_bits >
Ben Lindstrom822b6342002-06-23 21:38:49 +00001551 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1552 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1553 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1554 SSH_KEY_BITS_RESERVED) {
Damien Millereba71ba2000-04-29 23:57:08 +10001555 options.server_key_bits =
Ben Lindstrom822b6342002-06-23 21:38:49 +00001556 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1557 SSH_KEY_BITS_RESERVED;
Damien Millereba71ba2000-04-29 23:57:08 +10001558 debug("Forcing server key to %d bits to make it differ from host key.",
1559 options.server_key_bits);
1560 }
1561 }
1562
Ben Lindstroma26ea632002-06-06 20:46:25 +00001563 if (use_privsep) {
Ben Lindstroma26ea632002-06-06 20:46:25 +00001564 struct stat st;
1565
Ben Lindstroma26ea632002-06-06 20:46:25 +00001566 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1567 (S_ISDIR(st.st_mode) == 0))
1568 fatal("Missing privilege separation directory: %s",
1569 _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstrom59627352002-06-27 18:02:21 +00001570
1571#ifdef HAVE_CYGWIN
1572 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1573 (st.st_uid != getuid () ||
1574 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1575#else
Ben Lindstrom2dfacb32002-06-23 00:33:47 +00001576 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
Ben Lindstrom59627352002-06-27 18:02:21 +00001577#endif
Damien Miller180fc5b2003-02-24 11:50:18 +11001578 fatal("%s must be owned by root and not group or "
1579 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstroma26ea632002-06-06 20:46:25 +00001580 }
1581
Darren Tuckere7140f22008-06-10 23:01:51 +10001582 if (test_flag > 1) {
1583 if (test_user != NULL && test_addr != NULL && test_host != NULL)
1584 parse_server_match_config(&options, test_user,
1585 test_host, test_addr);
1586 dump_config(&options);
1587 }
1588
Ben Lindstrom794325a2001-08-06 21:09:07 +00001589 /* Configuration looks good, so exit if in test mode. */
1590 if (test_flag)
1591 exit(0);
1592
Damien Miller87aea252002-05-10 12:20:24 +10001593 /*
1594 * Clear out any supplemental groups we may have inherited. This
1595 * prevents inadvertent creation of files with bad modes (in the
Damien Millera8e06ce2003-11-21 23:48:55 +11001596 * portable version at least, it's certainly possible for PAM
1597 * to create a file, and we can't control the code in every
Damien Miller87aea252002-05-10 12:20:24 +10001598 * module which might be used).
1599 */
1600 if (setgroups(0, NULL) < 0)
1601 debug("setgroups() failed: %.200s", strerror(errno));
1602
Darren Tucker645ab752004-06-25 13:33:20 +10001603 if (rexec_flag) {
Damien Miller07d86be2006-03-26 14:19:21 +11001604 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
Darren Tucker645ab752004-06-25 13:33:20 +10001605 for (i = 0; i < rexec_argc; i++) {
1606 debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1607 rexec_argv[i] = saved_argv[i];
1608 }
1609 rexec_argv[rexec_argc] = "-R";
1610 rexec_argv[rexec_argc + 1] = NULL;
1611 }
1612
Damien Miller6ca16c62008-06-16 07:50:58 +10001613 /* Ensure that umask disallows at least group and world write */
1614 new_umask = umask(0077) | 0022;
1615 (void) umask(new_umask);
1616
Damien Millereba71ba2000-04-29 23:57:08 +10001617 /* Initialize the log (it is reinitialized below in case we forked). */
Darren Tuckerea7c8122005-01-20 11:03:08 +11001618 if (debug_flag && (!inetd_flag || rexeced_flag))
Damien Miller95def091999-11-25 00:26:21 +11001619 log_stderr = 1;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001620 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001621
Damien Millereba71ba2000-04-29 23:57:08 +10001622 /*
1623 * If not in debugging mode, and not started from inetd, disconnect
1624 * from the controlling terminal, and fork. The original process
1625 * exits.
1626 */
Ben Lindstromc72745a2000-12-02 19:03:54 +00001627 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
Damien Miller95def091999-11-25 00:26:21 +11001628#ifdef TIOCNOTTY
1629 int fd;
1630#endif /* TIOCNOTTY */
1631 if (daemon(0, 0) < 0)
1632 fatal("daemon() failed: %.200s", strerror(errno));
1633
1634 /* Disconnect from the controlling tty. */
1635#ifdef TIOCNOTTY
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001636 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +11001637 if (fd >= 0) {
1638 (void) ioctl(fd, TIOCNOTTY, NULL);
1639 close(fd);
1640 }
1641#endif /* TIOCNOTTY */
1642 }
1643 /* Reinitialize the log (because of the fork above). */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001644 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001645
Damien Miller95def091999-11-25 00:26:21 +11001646 /* Initialize the random number generator. */
1647 arc4random_stir();
1648
1649 /* Chdir to the root directory so that the current disk can be
1650 unmounted if desired. */
1651 chdir("/");
Damien Miller9f0f5c62001-12-21 14:45:46 +11001652
Ben Lindstromde71cda2001-03-24 00:43:26 +00001653 /* ignore SIGPIPE */
1654 signal(SIGPIPE, SIG_IGN);
Damien Miller95def091999-11-25 00:26:21 +11001655
Damien Millera1f68402006-08-19 00:31:39 +10001656 /* Get a connection, either from inetd or a listening TCP socket */
Damien Miller95def091999-11-25 00:26:21 +11001657 if (inetd_flag) {
Damien Millera1f68402006-08-19 00:31:39 +10001658 server_accept_inetd(&sock_in, &sock_out);
Damien Miller95def091999-11-25 00:26:21 +11001659 } else {
Darren Tuckerc8802aa2009-12-08 13:39:48 +11001660 platform_pre_listen();
Damien Millera1f68402006-08-19 00:31:39 +10001661 server_listen();
Damien Miller34132e52000-01-14 15:45:46 +11001662
Ben Lindstrom98097862001-06-25 05:10:20 +00001663 if (options.protocol & SSH_PROTO_1)
1664 generate_ephemeral_server_key();
1665
Ben Lindstrom98097862001-06-25 05:10:20 +00001666 signal(SIGHUP, sighup_handler);
Damien Millera1f68402006-08-19 00:31:39 +10001667 signal(SIGCHLD, main_sigchld_handler);
Ben Lindstrom98097862001-06-25 05:10:20 +00001668 signal(SIGTERM, sigterm_handler);
1669 signal(SIGQUIT, sigterm_handler);
1670
Damien Millera1f68402006-08-19 00:31:39 +10001671 /*
1672 * Write out the pid file after the sigterm handler
1673 * is setup and the listen sockets are bound
1674 */
Damien Miller95def091999-11-25 00:26:21 +11001675 if (!debug_flag) {
Damien Millera1f68402006-08-19 00:31:39 +10001676 FILE *f = fopen(options.pid_file, "w");
1677
Darren Tuckere5327042003-07-03 13:40:44 +10001678 if (f == NULL) {
1679 error("Couldn't create pid file \"%s\": %s",
1680 options.pid_file, strerror(errno));
1681 } else {
Ben Lindstromce0f6342002-06-11 16:42:49 +00001682 fprintf(f, "%ld\n", (long) getpid());
Damien Miller95def091999-11-25 00:26:21 +11001683 fclose(f);
1684 }
1685 }
Damien Miller95def091999-11-25 00:26:21 +11001686
Damien Millera1f68402006-08-19 00:31:39 +10001687 /* Accept a connection and return in a forked child */
1688 server_accept_loop(&sock_in, &sock_out,
1689 &newsock, config_s);
Damien Miller95def091999-11-25 00:26:21 +11001690 }
1691
1692 /* This is the child processing a new connection. */
Damien Miller57aae982004-03-08 23:11:25 +11001693 setproctitle("%s", "[accepted]");
Damien Miller95def091999-11-25 00:26:21 +11001694
Darren Tucker6832b832004-08-12 22:36:51 +10001695 /*
1696 * Create a new session and process group since the 4.4BSD
1697 * setlogin() affects the entire process group. We don't
1698 * want the child to be able to affect the parent.
1699 */
1700#if !defined(SSHD_ACQUIRES_CTTY)
1701 /*
1702 * If setsid is called, on some platforms sshd will later acquire a
1703 * controlling terminal which will result in "could not set
1704 * controlling tty" errors.
1705 */
1706 if (!debug_flag && !inetd_flag && setsid() < 0)
1707 error("setsid: %.100s", strerror(errno));
1708#endif
1709
Darren Tucker645ab752004-06-25 13:33:20 +10001710 if (rexec_flag) {
1711 int fd;
1712
Damien Miller035a5b42004-06-26 08:16:31 +10001713 debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1714 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001715 dup2(newsock, STDIN_FILENO);
1716 dup2(STDIN_FILENO, STDOUT_FILENO);
1717 if (startup_pipe == -1)
Damien Miller035a5b42004-06-26 08:16:31 +10001718 close(REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001719 else
Damien Miller035a5b42004-06-26 08:16:31 +10001720 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001721
Damien Miller035a5b42004-06-26 08:16:31 +10001722 dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001723 close(config_s[1]);
Darren Tuckerd8835932004-08-12 22:42:29 +10001724 if (startup_pipe != -1)
1725 close(startup_pipe);
Damien Miller035a5b42004-06-26 08:16:31 +10001726
Darren Tucker645ab752004-06-25 13:33:20 +10001727 execv(rexec_argv[0], rexec_argv);
1728
1729 /* Reexec has failed, fall back and continue */
1730 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
Damien Miller035a5b42004-06-26 08:16:31 +10001731 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
Darren Tucker645ab752004-06-25 13:33:20 +10001732 log_init(__progname, options.log_level,
1733 options.log_facility, log_stderr);
1734
1735 /* Clean up fds */
Damien Miller035a5b42004-06-26 08:16:31 +10001736 startup_pipe = REEXEC_STARTUP_PIPE_FD;
Darren Tucker645ab752004-06-25 13:33:20 +10001737 close(config_s[1]);
Damien Miller035a5b42004-06-26 08:16:31 +10001738 close(REEXEC_CONFIG_PASS_FD);
1739 newsock = sock_out = sock_in = dup(STDIN_FILENO);
Darren Tucker645ab752004-06-25 13:33:20 +10001740 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1741 dup2(fd, STDIN_FILENO);
1742 dup2(fd, STDOUT_FILENO);
1743 if (fd > STDERR_FILENO)
1744 close(fd);
1745 }
Damien Miller035a5b42004-06-26 08:16:31 +10001746 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1747 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001748 }
1749
Damien Miller5428f641999-11-25 11:54:57 +11001750 /*
1751 * Disable the key regeneration alarm. We will not regenerate the
1752 * key since we are no longer in a position to give it to anyone. We
1753 * will not restart on SIGHUP since it no longer makes sense.
1754 */
Damien Miller95def091999-11-25 00:26:21 +11001755 alarm(0);
1756 signal(SIGALRM, SIG_DFL);
1757 signal(SIGHUP, SIG_DFL);
1758 signal(SIGTERM, SIG_DFL);
1759 signal(SIGQUIT, SIG_DFL);
1760 signal(SIGCHLD, SIG_DFL);
Damien Miller4e0f5e12000-08-29 11:05:50 +11001761 signal(SIGINT, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +11001762
Damien Miller5428f641999-11-25 11:54:57 +11001763 /*
1764 * Register our connection. This turns encryption off because we do
1765 * not have a key.
1766 */
Damien Miller95def091999-11-25 00:26:21 +11001767 packet_set_connection(sock_in, sock_out);
Damien Miller9786e6e2005-07-26 21:54:56 +10001768 packet_set_server();
Damien Miller95def091999-11-25 00:26:21 +11001769
Damien Miller4f1d6b22005-05-26 11:59:32 +10001770 /* Set SO_KEEPALIVE if requested. */
1771 if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1772 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1773 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1774
Damien Miller677257f2005-06-17 12:55:03 +10001775 if ((remote_port = get_remote_port()) < 0) {
1776 debug("get_remote_port failed");
1777 cleanup_exit(255);
1778 }
Damien Miller4d3fd542005-11-05 15:13:24 +11001779
1780 /*
1781 * We use get_canonical_hostname with usedns = 0 instead of
1782 * get_remote_ipaddr here so IP options will be checked.
1783 */
Damien Millereb13e552006-06-13 13:03:53 +10001784 (void) get_canonical_hostname(0);
1785 /*
1786 * The rest of the code depends on the fact that
1787 * get_remote_ipaddr() caches the remote ip, even if
1788 * the socket goes away.
1789 */
1790 remote_ip = get_remote_ipaddr();
Damien Miller95def091999-11-25 00:26:21 +11001791
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001792#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11001793 audit_connection_from(remote_ip, remote_port);
1794#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001795#ifdef LIBWRAP
Darren Tucker1f1e17b2008-02-28 23:20:48 +11001796 allow_severity = options.log_facility|LOG_INFO;
1797 deny_severity = options.log_facility|LOG_WARNING;
Damien Miller6a4a4b92001-11-12 11:07:11 +11001798 /* Check whether logins are denied from this host. */
Darren Tucker586b0b92004-06-25 13:34:31 +10001799 if (packet_connection_is_on_socket()) {
Damien Miller95def091999-11-25 00:26:21 +11001800 struct request_info req;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001801
Ben Lindstromce89dac2001-09-12 16:58:04 +00001802 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
Damien Miller95def091999-11-25 00:26:21 +11001803 fromhost(&req);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001804
Damien Miller95def091999-11-25 00:26:21 +11001805 if (!hosts_access(&req)) {
Damien Miller6a4a4b92001-11-12 11:07:11 +11001806 debug("Connection refused by tcp wrapper");
Ben Lindstrom7de696e2001-03-29 00:45:12 +00001807 refuse(&req);
Damien Miller6a4a4b92001-11-12 11:07:11 +11001808 /* NOTREACHED */
1809 fatal("libwrap refuse returns");
Damien Miller95def091999-11-25 00:26:21 +11001810 }
Damien Miller95def091999-11-25 00:26:21 +11001811 }
Damien Miller34132e52000-01-14 15:45:46 +11001812#endif /* LIBWRAP */
Damien Miller6a4a4b92001-11-12 11:07:11 +11001813
Damien Miller95def091999-11-25 00:26:21 +11001814 /* Log the connection. */
1815 verbose("Connection from %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001816
Damien Miller5428f641999-11-25 11:54:57 +11001817 /*
Damien Miller788f2122005-11-05 15:14:59 +11001818 * We don't want to listen forever unless the other side
Damien Miller5428f641999-11-25 11:54:57 +11001819 * successfully authenticates itself. So we set up an alarm which is
1820 * cleared after successful authentication. A limit of zero
Damien Miller788f2122005-11-05 15:14:59 +11001821 * indicates no limit. Note that we don't set the alarm in debugging
Damien Miller5428f641999-11-25 11:54:57 +11001822 * mode; it is just annoying to have the server exit just when you
1823 * are about to discover the bug.
1824 */
Ben Lindstrom5ade9ab2003-08-25 01:16:21 +00001825 signal(SIGALRM, grace_alarm_handler);
Damien Miller95def091999-11-25 00:26:21 +11001826 if (!debug_flag)
1827 alarm(options.login_grace_time);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001828
Damien Millerb38eff82000-04-01 11:09:21 +10001829 sshd_exchange_identification(sock_in, sock_out);
Darren Tuckerec960f22003-08-13 20:37:05 +10001830
Darren Tucker58911162008-01-01 20:33:09 +11001831 /* In inetd mode, generate ephemeral key only for proto 1 connections */
1832 if (!compat20 && inetd_flag && sensitive_data.server_key == NULL)
1833 generate_ephemeral_server_key();
1834
Damien Miller95def091999-11-25 00:26:21 +11001835 packet_set_nonblocking();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001836
Darren Tucker3e33cec2003-10-02 16:12:36 +10001837 /* allocate authentication context */
Damien Miller07d86be2006-03-26 14:19:21 +11001838 authctxt = xcalloc(1, sizeof(*authctxt));
Darren Tucker3e33cec2003-10-02 16:12:36 +10001839
Darren Tuckerf3bb4342005-03-31 21:39:25 +10001840 authctxt->loginmsg = &loginmsg;
1841
Darren Tucker3e33cec2003-10-02 16:12:36 +10001842 /* XXX global for cleanup, access from other modules */
1843 the_authctxt = authctxt;
1844
Darren Tucker5c14c732005-01-24 21:55:49 +11001845 /* prepare buffer to collect messages to display to user after login */
1846 buffer_init(&loginmsg);
1847
Ben Lindstrom943481c2002-03-22 03:43:46 +00001848 if (use_privsep)
Darren Tucker3e33cec2003-10-02 16:12:36 +10001849 if (privsep_preauth(authctxt) == 1)
Ben Lindstrom943481c2002-03-22 03:43:46 +00001850 goto authenticated;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001851
Damien Miller396691a2000-01-20 22:44:08 +11001852 /* perform the key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001853 /* authenticate user and start session */
Damien Millerefb4afe2000-04-12 18:45:05 +10001854 if (compat20) {
1855 do_ssh2_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001856 do_authentication2(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001857 } else {
1858 do_ssh1_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001859 do_authentication(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001860 }
Ben Lindstrom943481c2002-03-22 03:43:46 +00001861 /*
1862 * If we use privilege separation, the unprivileged child transfers
1863 * the current keystate and exits
1864 */
1865 if (use_privsep) {
Ben Lindstrom7339b2a2002-05-15 16:25:01 +00001866 mm_send_keystate(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001867 exit(0);
Ben Lindstrom943481c2002-03-22 03:43:46 +00001868 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001869
1870 authenticated:
Damien Miller7bff1a92005-12-24 14:59:12 +11001871 /*
1872 * Cancel the alarm we set to limit the time taken for
1873 * authentication.
1874 */
1875 alarm(0);
1876 signal(SIGALRM, SIG_DFL);
Damien Miller3f8123c2006-08-19 00:32:46 +10001877 authctxt->authenticated = 1;
Damien Miller7bff1a92005-12-24 14:59:12 +11001878 if (startup_pipe != -1) {
1879 close(startup_pipe);
1880 startup_pipe = -1;
1881 }
1882
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001883#ifdef SSH_AUDIT_EVENTS
1884 audit_event(SSH_AUTH_SUCCESS);
Darren Tucker269a1ea2005-02-03 00:20:53 +11001885#endif
1886
Darren Tucker52358d62008-03-11 22:58:25 +11001887#ifdef GSSAPI
1888 if (options.gss_authentication) {
1889 temporarily_use_uid(authctxt->pw);
1890 ssh_gssapi_storecreds();
1891 restore_uid();
1892 }
1893#endif
1894#ifdef USE_PAM
1895 if (options.use_pam) {
1896 do_pam_setcred(1);
1897 do_pam_session();
1898 }
1899#endif
1900
Ben Lindstrom6328ab32002-03-22 02:54:23 +00001901 /*
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001902 * In privilege separation, we fork another child and prepare
1903 * file descriptor passing.
1904 */
1905 if (use_privsep) {
Ben Lindstrom943481c2002-03-22 03:43:46 +00001906 privsep_postauth(authctxt);
1907 /* the monitor process [priv] will not return */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001908 if (!compat20)
1909 destroy_sensitive_data();
1910 }
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001911
Darren Tucker3fc464e2008-06-13 06:42:45 +10001912 packet_set_timeout(options.client_alive_interval,
1913 options.client_alive_count_max);
1914
Darren Tucker3e33cec2003-10-02 16:12:36 +10001915 /* Start session. */
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001916 do_authenticated(authctxt);
1917
Damien Miller3a5b0232002-03-13 13:19:42 +11001918 /* The connection has been terminated. */
Damien Millerb61f3fc2008-07-11 17:36:48 +10001919 packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes);
1920 packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes);
1921 verbose("Transferred: sent %llu, received %llu bytes", obytes, ibytes);
1922
1923 verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001924
Damien Millerbeb4ba51999-12-28 15:09:35 +11001925#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +10001926 if (options.use_pam)
1927 finish_pam();
Damien Millerbeb4ba51999-12-28 15:09:35 +11001928#endif /* USE_PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001929
Darren Tucker2b59a6d2005-03-06 22:38:51 +11001930#ifdef SSH_AUDIT_EVENTS
1931 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE));
1932#endif
1933
Damien Miller95def091999-11-25 00:26:21 +11001934 packet_close();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001935
1936 if (use_privsep)
1937 mm_terminate();
1938
Damien Miller95def091999-11-25 00:26:21 +11001939 exit(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001940}
1941
Damien Miller95def091999-11-25 00:26:21 +11001942/*
Ben Lindstromabcb1452002-03-22 01:10:21 +00001943 * Decrypt session_key_int using our private server key and private host key
1944 * (key with larger modulus first).
1945 */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001946int
Ben Lindstromabcb1452002-03-22 01:10:21 +00001947ssh1_session_key(BIGNUM *session_key_int)
1948{
1949 int rsafail = 0;
1950
Damien Millerf0b15df2006-03-26 13:59:20 +11001951 if (BN_cmp(sensitive_data.server_key->rsa->n,
1952 sensitive_data.ssh1_host_key->rsa->n) > 0) {
Ben Lindstromabcb1452002-03-22 01:10:21 +00001953 /* Server key has bigger modulus. */
1954 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
Damien Millerf0b15df2006-03-26 13:59:20 +11001955 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1956 SSH_KEY_BITS_RESERVED) {
1957 fatal("do_connection: %s: "
1958 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
Ben Lindstromabcb1452002-03-22 01:10:21 +00001959 get_remote_ipaddr(),
1960 BN_num_bits(sensitive_data.server_key->rsa->n),
1961 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1962 SSH_KEY_BITS_RESERVED);
1963 }
1964 if (rsa_private_decrypt(session_key_int, session_key_int,
1965 sensitive_data.server_key->rsa) <= 0)
1966 rsafail++;
1967 if (rsa_private_decrypt(session_key_int, session_key_int,
1968 sensitive_data.ssh1_host_key->rsa) <= 0)
1969 rsafail++;
1970 } else {
1971 /* Host key has bigger modulus (or they are equal). */
1972 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
Damien Millerf0b15df2006-03-26 13:59:20 +11001973 BN_num_bits(sensitive_data.server_key->rsa->n) +
1974 SSH_KEY_BITS_RESERVED) {
1975 fatal("do_connection: %s: "
1976 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
Ben Lindstromabcb1452002-03-22 01:10:21 +00001977 get_remote_ipaddr(),
1978 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1979 BN_num_bits(sensitive_data.server_key->rsa->n),
1980 SSH_KEY_BITS_RESERVED);
1981 }
1982 if (rsa_private_decrypt(session_key_int, session_key_int,
1983 sensitive_data.ssh1_host_key->rsa) < 0)
1984 rsafail++;
1985 if (rsa_private_decrypt(session_key_int, session_key_int,
1986 sensitive_data.server_key->rsa) < 0)
1987 rsafail++;
1988 }
1989 return (rsafail);
1990}
1991/*
Damien Miller396691a2000-01-20 22:44:08 +11001992 * SSH1 key exchange
Damien Miller95def091999-11-25 00:26:21 +11001993 */
Ben Lindstrombba81212001-06-25 05:01:22 +00001994static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001995do_ssh1_kex(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001996{
Damien Miller95def091999-11-25 00:26:21 +11001997 int i, len;
Damien Miller7650bc62001-01-30 09:27:26 +11001998 int rsafail = 0;
Damien Miller95def091999-11-25 00:26:21 +11001999 BIGNUM *session_key_int;
Ben Lindstrom46c16222000-12-22 01:43:59 +00002000 u_char session_key[SSH_SESSION_KEY_LENGTH];
2001 u_char cookie[8];
2002 u_int cipher_type, auth_mask, protocol_flags;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002003
Damien Miller5428f641999-11-25 11:54:57 +11002004 /*
2005 * Generate check bytes that the client must send back in the user
2006 * packet in order for it to be accepted; this is used to defy ip
2007 * spoofing attacks. Note that this only works against somebody
2008 * doing IP spoofing from a remote machine; any machine on the local
2009 * network can still see outgoing packets and catch the random
2010 * cookie. This only affects rhosts authentication, and this is one
2011 * of the reasons why it is inherently insecure.
2012 */
Damien Miller354c48c2008-05-19 14:50:00 +10002013 arc4random_buf(cookie, sizeof(cookie));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002014
Damien Miller5428f641999-11-25 11:54:57 +11002015 /*
2016 * Send our public key. We include in the packet 64 bits of random
2017 * data that must be matched in the reply in order to prevent IP
2018 * spoofing.
2019 */
Damien Miller95def091999-11-25 00:26:21 +11002020 packet_start(SSH_SMSG_PUBLIC_KEY);
2021 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11002022 packet_put_char(cookie[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002023
Damien Miller95def091999-11-25 00:26:21 +11002024 /* Store our public server RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11002025 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
2026 packet_put_bignum(sensitive_data.server_key->rsa->e);
2027 packet_put_bignum(sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002028
Damien Miller95def091999-11-25 00:26:21 +11002029 /* Store our public host RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11002030 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
2031 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
2032 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002033
Damien Miller95def091999-11-25 00:26:21 +11002034 /* Put protocol flags. */
2035 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002036
Damien Miller95def091999-11-25 00:26:21 +11002037 /* Declare which ciphers we support. */
Damien Miller874d77b2000-10-14 16:23:11 +11002038 packet_put_int(cipher_mask_ssh1(0));
Damien Miller95def091999-11-25 00:26:21 +11002039
2040 /* Declare supported authentication types. */
2041 auth_mask = 0;
Damien Miller95def091999-11-25 00:26:21 +11002042 if (options.rhosts_rsa_authentication)
2043 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
2044 if (options.rsa_authentication)
2045 auth_mask |= 1 << SSH_AUTH_RSA;
Ben Lindstrom551ea372001-06-05 18:56:16 +00002046 if (options.challenge_response_authentication == 1)
Damien Miller95def091999-11-25 00:26:21 +11002047 auth_mask |= 1 << SSH_AUTH_TIS;
Damien Miller95def091999-11-25 00:26:21 +11002048 if (options.password_authentication)
2049 auth_mask |= 1 << SSH_AUTH_PASSWORD;
2050 packet_put_int(auth_mask);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002051
Damien Miller95def091999-11-25 00:26:21 +11002052 /* Send the packet and wait for it to be sent. */
2053 packet_send();
2054 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002055
Damien Miller0bc1bd82000-11-13 22:57:25 +11002056 debug("Sent %d bit server key and %d bit host key.",
2057 BN_num_bits(sensitive_data.server_key->rsa->n),
2058 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002059
Damien Miller95def091999-11-25 00:26:21 +11002060 /* Read clients reply (cipher type and session key). */
Damien Millerdff50992002-01-22 23:16:32 +11002061 packet_read_expect(SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002062
Damien Miller50945fa1999-12-09 10:31:37 +11002063 /* Get cipher type and check whether we accept this. */
Damien Miller95def091999-11-25 00:26:21 +11002064 cipher_type = packet_get_char();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002065
Damien Miller874d77b2000-10-14 16:23:11 +11002066 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
Damien Miller50945fa1999-12-09 10:31:37 +11002067 packet_disconnect("Warning: client selects unsupported cipher.");
2068
Damien Miller95def091999-11-25 00:26:21 +11002069 /* Get check bytes from the packet. These must match those we
2070 sent earlier with the public key packet. */
2071 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11002072 if (cookie[i] != packet_get_char())
Damien Miller95def091999-11-25 00:26:21 +11002073 packet_disconnect("IP Spoofing check bytes do not match.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002074
Damien Miller95def091999-11-25 00:26:21 +11002075 debug("Encryption type: %.200s", cipher_name(cipher_type));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002076
Damien Miller95def091999-11-25 00:26:21 +11002077 /* Get the encrypted integer. */
Damien Millerda755162002-01-22 23:09:22 +11002078 if ((session_key_int = BN_new()) == NULL)
2079 fatal("do_ssh1_kex: BN_new failed");
Damien Millerd432ccf2002-01-22 23:14:44 +11002080 packet_get_bignum(session_key_int);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002081
Damien Miller95def091999-11-25 00:26:21 +11002082 protocol_flags = packet_get_int();
2083 packet_set_protocol_flags(protocol_flags);
Damien Miller48b03fc2002-01-22 23:11:40 +11002084 packet_check_eom();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002085
Ben Lindstromabcb1452002-03-22 01:10:21 +00002086 /* Decrypt session_key_int using host/server keys */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002087 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
2088
Damien Miller5428f641999-11-25 11:54:57 +11002089 /*
2090 * Extract session key from the decrypted integer. The key is in the
2091 * least significant 256 bits of the integer; the first byte of the
2092 * key is in the highest bits.
2093 */
Damien Miller7650bc62001-01-30 09:27:26 +11002094 if (!rsafail) {
Darren Tucker0bc85572006-11-07 23:14:41 +11002095 (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8);
Damien Miller7650bc62001-01-30 09:27:26 +11002096 len = BN_num_bytes(session_key_int);
Damien Millereccb9de2005-06-17 12:59:34 +10002097 if (len < 0 || (u_int)len > sizeof(session_key)) {
Darren Tucker0bc85572006-11-07 23:14:41 +11002098 error("do_ssh1_kex: bad session key len from %s: "
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00002099 "session_key_int %d > sizeof(session_key) %lu",
2100 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
Damien Miller7650bc62001-01-30 09:27:26 +11002101 rsafail++;
2102 } else {
2103 memset(session_key, 0, sizeof(session_key));
2104 BN_bn2bin(session_key_int,
2105 session_key + sizeof(session_key) - len);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002106
Darren Tuckere14e0052004-05-13 16:30:44 +10002107 derive_ssh1_session_id(
Darren Tuckerfc959702004-07-17 16:12:08 +10002108 sensitive_data.ssh1_host_key->rsa->n,
Darren Tuckere14e0052004-05-13 16:30:44 +10002109 sensitive_data.server_key->rsa->n,
2110 cookie, session_id);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002111 /*
2112 * Xor the first 16 bytes of the session key with the
2113 * session id.
2114 */
2115 for (i = 0; i < 16; i++)
2116 session_key[i] ^= session_id[i];
Damien Miller7650bc62001-01-30 09:27:26 +11002117 }
2118 }
2119 if (rsafail) {
Ben Lindstromeb648a72001-03-05 06:00:29 +00002120 int bytes = BN_num_bytes(session_key_int);
Ben Lindstrom13c5d3b2002-02-26 18:00:48 +00002121 u_char *buf = xmalloc(bytes);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002122 MD5_CTX md;
2123
Damien Miller996acd22003-04-09 20:59:48 +10002124 logit("do_connection: generating a fake encryption key");
Ben Lindstromeb648a72001-03-05 06:00:29 +00002125 BN_bn2bin(session_key_int, buf);
2126 MD5_Init(&md);
2127 MD5_Update(&md, buf, bytes);
2128 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
2129 MD5_Final(session_key, &md);
2130 MD5_Init(&md);
2131 MD5_Update(&md, session_key, 16);
2132 MD5_Update(&md, buf, bytes);
2133 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
2134 MD5_Final(session_key + 16, &md);
2135 memset(buf, 0, bytes);
2136 xfree(buf);
Ben Lindstrom941ac822001-03-05 06:25:23 +00002137 for (i = 0; i < 16; i++)
2138 session_id[i] = session_key[i] ^ session_key[i + 16];
Damien Miller7650bc62001-01-30 09:27:26 +11002139 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002140 /* Destroy the private and public keys. No longer. */
Damien Miller3a5b0232002-03-13 13:19:42 +11002141 destroy_sensitive_data();
Ben Lindstromeb648a72001-03-05 06:00:29 +00002142
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002143 if (use_privsep)
2144 mm_ssh1_session_id(session_id);
2145
Damien Miller396691a2000-01-20 22:44:08 +11002146 /* Destroy the decrypted integer. It is no longer needed. */
2147 BN_clear_free(session_key_int);
2148
Damien Miller95def091999-11-25 00:26:21 +11002149 /* Set the session key. From this on all communications will be encrypted. */
2150 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002151
Damien Miller95def091999-11-25 00:26:21 +11002152 /* Destroy our copy of the session key. It is no longer needed. */
2153 memset(session_key, 0, sizeof(session_key));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002154
Damien Miller95def091999-11-25 00:26:21 +11002155 debug("Received session key; encryption turned on.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002156
Ben Lindstromf666fec2002-06-06 19:51:58 +00002157 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
Damien Miller95def091999-11-25 00:26:21 +11002158 packet_start(SSH_SMSG_SUCCESS);
2159 packet_send();
2160 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002161}
Damien Millerefb4afe2000-04-12 18:45:05 +10002162
2163/*
2164 * SSH2 key exchange: diffie-hellman-group1-sha1
2165 */
Ben Lindstrombba81212001-06-25 05:01:22 +00002166static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00002167do_ssh2_kex(void)
Damien Millerefb4afe2000-04-12 18:45:05 +10002168{
Damien Millerefb4afe2000-04-12 18:45:05 +10002169 Kex *kex;
Damien Millerefb4afe2000-04-12 18:45:05 +10002170
Damien Miller78928792000-04-12 20:17:38 +10002171 if (options.ciphers != NULL) {
Damien Miller4af51302000-04-16 11:18:38 +10002172 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
Damien Miller78928792000-04-12 20:17:38 +10002173 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
2174 }
Damien Millera0ff4662001-03-30 10:49:35 +10002175 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
2176 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
2177 myproposal[PROPOSAL_ENC_ALGS_STOC] =
2178 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
2179
Ben Lindstrom06b33aa2001-02-15 03:01:59 +00002180 if (options.macs != NULL) {
2181 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2182 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2183 }
Damien Miller9786e6e2005-07-26 21:54:56 +10002184 if (options.compression == COMP_NONE) {
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002185 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2186 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
Damien Miller9786e6e2005-07-26 21:54:56 +10002187 } else if (options.compression == COMP_DELAYED) {
2188 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2189 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002190 }
Damien Millerf0b15df2006-03-26 13:59:20 +11002191
Damien Miller0bc1bd82000-11-13 22:57:25 +11002192 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
2193
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002194 /* start key exchange */
Ben Lindstrom238abf62001-04-04 17:52:53 +00002195 kex = kex_setup(myproposal);
Damien Miller8e7fb332003-02-24 12:03:03 +11002196 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
Damien Millerf675fc42004-06-15 10:30:09 +10002197 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
Damien Miller8e7fb332003-02-24 12:03:03 +11002198 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
Damien Millera63128d2006-03-15 12:08:28 +11002199 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002200 kex->server = 1;
2201 kex->client_version_string=client_version_string;
2202 kex->server_version_string=server_version_string;
2203 kex->load_host_key=&get_hostkey_by_type;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002204 kex->host_key_index=&get_hostkey_index;
Damien Millerefb4afe2000-04-12 18:45:05 +10002205
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002206 xxx_kex = kex;
2207
Ben Lindstrombe2cc432001-04-04 23:46:07 +00002208 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
Damien Miller874d77b2000-10-14 16:23:11 +11002209
Ben Lindstrom2d90e002001-04-04 02:00:54 +00002210 session_id2 = kex->session_id;
2211 session_id2_len = kex->session_id_len;
2212
Damien Miller874d77b2000-10-14 16:23:11 +11002213#ifdef DEBUG_KEXDH
2214 /* send 1st encrypted/maced/compressed message */
2215 packet_start(SSH2_MSG_IGNORE);
2216 packet_put_cstring("markus");
2217 packet_send();
2218 packet_write_wait();
2219#endif
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002220 debug("KEX done");
Damien Millerefb4afe2000-04-12 18:45:05 +10002221}
Darren Tucker3e33cec2003-10-02 16:12:36 +10002222
2223/* server specific fatal cleanup */
2224void
2225cleanup_exit(int i)
2226{
2227 if (the_authctxt)
2228 do_cleanup(the_authctxt);
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002229#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11002230 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
2231 if (!use_privsep || mm_is_monitor())
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002232 audit_event(SSH_CONNECTION_ABANDON);
Darren Tucker269a1ea2005-02-03 00:20:53 +11002233#endif
Darren Tucker3e33cec2003-10-02 16:12:36 +10002234 _exit(i);
2235}