blob: 5ea87f0f91b7ab53d61684909a1936622335bd98 [file] [log] [blame]
Damien Miller2ee0c432008-03-07 18:31:47 +11001/* $OpenBSD: sshd.c,v 1.355 2008/02/14 13:10:31 mbalmer 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 Miller9cf6d072006-03-15 11:29:24 +110057#include <sys/wait.h>
Damien Miller03e20032006-03-15 11:16:59 +110058
Darren Tucker39972492006-07-12 22:22:46 +100059#include <errno.h>
Damien Miller57cf6382006-07-10 21:13:46 +100060#include <fcntl.h>
Damien Millerb8fe89c2006-07-24 14:51:00 +100061#include <netdb.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110062#ifdef HAVE_PATHS_H
Damien Miller03e20032006-03-15 11:16:59 +110063#include <paths.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110064#endif
Damien Millera1738e42006-07-10 21:33:04 +100065#include <grp.h>
Damien Miller9f2abc42006-07-10 20:53:08 +100066#include <pwd.h>
Damien Miller6ff3cad2006-03-15 11:52:09 +110067#include <signal.h>
Damien Millerded319c2006-09-01 15:38:36 +100068#include <stdarg.h>
Damien Millera7a73ee2006-08-05 11:37:59 +100069#include <stdio.h>
Damien Millere7a1e5c2006-08-05 11:34:19 +100070#include <stdlib.h>
Damien Millere3476ed2006-07-24 14:13:33 +100071#include <string.h>
Damien Miller75bb6642006-08-05 14:07:20 +100072#include <unistd.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100073
Ben Lindstrom226cfa02001-01-22 05:34:40 +000074#include <openssl/dh.h>
75#include <openssl/bn.h>
Damien Miller6a47f302002-02-13 13:55:06 +110076#include <openssl/md5.h>
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000077#include <openssl/rand.h>
Darren Tuckerbfaaf962008-02-28 19:13:52 +110078#include "openbsd-compat/openssl-compat.h"
79
Kevin Steves0ea1d9d2002-04-25 18:17:04 +000080#ifdef HAVE_SECUREWARE
81#include <sys/security.h>
82#include <prot.h>
83#endif
Ben Lindstrom226cfa02001-01-22 05:34:40 +000084
Damien Millerd7834352006-08-05 12:39:39 +100085#include "xmalloc.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000086#include "ssh.h"
87#include "ssh1.h"
88#include "ssh2.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100089#include "rsa.h"
Ben Lindstromd95c09c2001-02-18 19:13:33 +000090#include "sshpty.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100091#include "packet.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000092#include "log.h"
Damien Millerd7834352006-08-05 12:39:39 +100093#include "buffer.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100094#include "servconf.h"
95#include "uidswap.h"
96#include "compat.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000097#include "cipher.h"
Damien Millerb38eff82000-04-01 11:09:21 +100098#include "key.h"
Damien Millerd7834352006-08-05 12:39:39 +100099#include "kex.h"
Damien Miller874d77b2000-10-14 16:23:11 +1100100#include "dh.h"
Damien Millerefb4afe2000-04-12 18:45:05 +1000101#include "myproposal.h"
Damien Millereba71ba2000-04-29 23:57:08 +1000102#include "authfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000103#include "pathnames.h"
104#include "atomicio.h"
105#include "canohost.h"
Damien Millerd7834352006-08-05 12:39:39 +1000106#include "hostfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000107#include "auth.h"
108#include "misc.h"
Darren Tucker645ab752004-06-25 13:33:20 +1000109#include "msg.h"
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +0000110#include "dispatch.h"
Ben Lindstrom1bae4042001-10-03 17:46:39 +0000111#include "channels.h"
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +0000112#include "session.h"
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000113#include "monitor_mm.h"
114#include "monitor.h"
Damien Millerd7834352006-08-05 12:39:39 +1000115#ifdef GSSAPI
116#include "ssh-gss.h"
117#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000118#include "monitor_wrap.h"
119#include "monitor_fdpass.h"
Damien Millerb7576772006-07-10 20:23:39 +1000120#include "version.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000121
122#ifdef LIBWRAP
123#include <tcpd.h>
124#include <syslog.h>
Darren Tucker1f1e17b2008-02-28 23:20:48 +1100125int allow_severity;
126int deny_severity;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000127#endif /* LIBWRAP */
128
129#ifndef O_NOCTTY
130#define O_NOCTTY 0
131#endif
132
Damien Miller035a5b42004-06-26 08:16:31 +1000133/* Re-exec fds */
134#define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
135#define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
136#define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
137#define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
138
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000139extern char *__progname;
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000140
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000141/* Server configuration options. */
142ServerOptions options;
143
144/* Name of the server configuration file. */
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000145char *config_file_name = _PATH_SERVER_CONFIG_FILE;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000146
Damien Miller4af51302000-04-16 11:18:38 +1000147/*
Damien Miller95def091999-11-25 00:26:21 +1100148 * Debug mode flag. This can be set on the command line. If debug
149 * mode is enabled, extra debugging output will be sent to the system
150 * log, the daemon will not go to background, and will exit after processing
151 * the first connection.
152 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000153int debug_flag = 0;
154
Ben Lindstrom794325a2001-08-06 21:09:07 +0000155/* Flag indicating that the daemon should only test the configuration and keys. */
156int test_flag = 0;
157
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000158/* Flag indicating that the daemon is being started from inetd. */
159int inetd_flag = 0;
160
Ben Lindstromc72745a2000-12-02 19:03:54 +0000161/* Flag indicating that sshd should not detach and become a daemon. */
162int no_daemon_flag = 0;
163
Damien Miller5ce662a1999-11-11 17:57:39 +1100164/* debug goes to stderr unless inetd_flag is set */
165int log_stderr = 0;
166
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000167/* Saved arguments to main(). */
168char **saved_argv;
Damien Millerb8c656e2000-06-28 15:22:41 +1000169int saved_argc;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000170
Darren Tucker645ab752004-06-25 13:33:20 +1000171/* re-exec */
172int rexeced_flag = 0;
173int rexec_flag = 1;
174int rexec_argc = 0;
175char **rexec_argv;
176
Damien Miller5428f641999-11-25 11:54:57 +1100177/*
Damien Miller34132e52000-01-14 15:45:46 +1100178 * The sockets that the server is listening; this is used in the SIGHUP
179 * signal handler.
Damien Miller5428f641999-11-25 11:54:57 +1100180 */
Damien Miller34132e52000-01-14 15:45:46 +1100181#define MAX_LISTEN_SOCKS 16
182int listen_socks[MAX_LISTEN_SOCKS];
183int num_listen_socks = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000184
Damien Miller5428f641999-11-25 11:54:57 +1100185/*
186 * the client's version string, passed by sshd2 in compat mode. if != NULL,
187 * sshd will skip the version-number exchange
188 */
Damien Miller95def091999-11-25 00:26:21 +1100189char *client_version_string = NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000190char *server_version_string = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000191
Ben Lindstrom8ac91062001-04-04 17:57:54 +0000192/* for rekeying XXX fixme */
193Kex *xxx_kex;
194
Damien Miller5428f641999-11-25 11:54:57 +1100195/*
196 * Any really sensitive data in the application is contained in this
197 * structure. The idea is that this structure could be locked into memory so
198 * that the pages do not get written into swap. However, there are some
199 * problems. The private key contains BIGNUMs, and we do not (in principle)
200 * have access to the internals of them, and locking just the structure is
201 * not very useful. Currently, memory locking is not implemented.
202 */
Damien Miller95def091999-11-25 00:26:21 +1100203struct {
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000204 Key *server_key; /* ephemeral server key */
Damien Miller0bc1bd82000-11-13 22:57:25 +1100205 Key *ssh1_host_key; /* ssh1 host key */
206 Key **host_keys; /* all private host keys */
207 int have_ssh1_key;
208 int have_ssh2_key;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000209 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000210} sensitive_data;
211
Damien Miller5428f641999-11-25 11:54:57 +1100212/*
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000213 * Flag indicating whether the RSA server key needs to be regenerated.
214 * Is set in the SIGALRM handler and cleared when the key is regenerated.
Damien Miller5428f641999-11-25 11:54:57 +1100215 */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000216static volatile sig_atomic_t key_do_regen = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000217
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000218/* This is set to true when a signal is received. */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000219static volatile sig_atomic_t received_sighup = 0;
220static volatile sig_atomic_t received_sigterm = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000221
Damien Millerb38eff82000-04-01 11:09:21 +1000222/* session identifier, used by RSA-auth */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000223u_char session_id[16];
Damien Millerb38eff82000-04-01 11:09:21 +1000224
Damien Millereba71ba2000-04-29 23:57:08 +1000225/* same for ssh2 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000226u_char *session_id2 = NULL;
Darren Tucker502d3842003-06-28 12:38:01 +1000227u_int session_id2_len = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000228
Damien Miller942da032000-08-18 13:59:06 +1000229/* record remote hostname or ip */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000230u_int utmp_len = MAXHOSTNAMELEN;
Damien Miller942da032000-08-18 13:59:06 +1000231
Ben Lindstromd84df982001-12-06 16:35:40 +0000232/* options.max_startup sized array of fd ints */
233int *startup_pipes = NULL;
234int startup_pipe; /* in child */
235
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000236/* variables used for privilege separation */
Darren Tucker45150472006-07-12 22:34:17 +1000237int use_privsep = -1;
Darren Tuckera8be9e22004-02-06 16:40:27 +1100238struct monitor *pmonitor = NULL;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000239
Darren Tucker3e33cec2003-10-02 16:12:36 +1000240/* global authentication context */
241Authctxt *the_authctxt = NULL;
242
Darren Tucker45150472006-07-12 22:34:17 +1000243/* sshd_config buffer */
244Buffer cfg;
245
Darren Tucker09991742004-07-17 17:05:14 +1000246/* message to be displayed after login */
247Buffer loginmsg;
248
Damien Miller6433df02006-09-07 10:36:43 +1000249/* Unprivileged user */
250struct passwd *privsep_pw = NULL;
251
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000252/* Prototypes for various functions defined later in this file. */
Ben Lindstrombba81212001-06-25 05:01:22 +0000253void destroy_sensitive_data(void);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000254void demote_sensitive_data(void);
Damien Miller98c7ad62000-03-09 21:27:49 +1100255
Ben Lindstrombba81212001-06-25 05:01:22 +0000256static void do_ssh1_kex(void);
257static void do_ssh2_kex(void);
Damien Miller874d77b2000-10-14 16:23:11 +1100258
Damien Miller98c7ad62000-03-09 21:27:49 +1100259/*
Damien Miller34132e52000-01-14 15:45:46 +1100260 * Close all listening sockets
261 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000262static void
Damien Miller34132e52000-01-14 15:45:46 +1100263close_listen_socks(void)
264{
265 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000266
Damien Miller34132e52000-01-14 15:45:46 +1100267 for (i = 0; i < num_listen_socks; i++)
268 close(listen_socks[i]);
269 num_listen_socks = -1;
270}
271
Ben Lindstromd84df982001-12-06 16:35:40 +0000272static void
273close_startup_pipes(void)
274{
275 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000276
Ben Lindstromd84df982001-12-06 16:35:40 +0000277 if (startup_pipes)
278 for (i = 0; i < options.max_startups; i++)
279 if (startup_pipes[i] != -1)
280 close(startup_pipes[i]);
281}
282
Damien Miller34132e52000-01-14 15:45:46 +1100283/*
Damien Miller95def091999-11-25 00:26:21 +1100284 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
285 * the effect is to reread the configuration file (and to regenerate
286 * the server key).
287 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100288
289/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000290static void
Damien Miller95def091999-11-25 00:26:21 +1100291sighup_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000292{
Ben Lindstrom07958482001-12-06 16:19:01 +0000293 int save_errno = errno;
294
Damien Miller95def091999-11-25 00:26:21 +1100295 received_sighup = 1;
296 signal(SIGHUP, sighup_handler);
Ben Lindstrom07958482001-12-06 16:19:01 +0000297 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000298}
299
Damien Miller95def091999-11-25 00:26:21 +1100300/*
301 * Called from the main program after receiving SIGHUP.
302 * Restarts the server.
303 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000304static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000305sighup_restart(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000306{
Damien Miller996acd22003-04-09 20:59:48 +1000307 logit("Received SIGHUP; restarting.");
Damien Miller34132e52000-01-14 15:45:46 +1100308 close_listen_socks();
Ben Lindstromd84df982001-12-06 16:35:40 +0000309 close_startup_pipes();
Darren Tuckered623962007-02-25 20:37:21 +1100310 alarm(0); /* alarm timer persists across exec */
Damien Miller95def091999-11-25 00:26:21 +1100311 execv(saved_argv[0], saved_argv);
Damien Miller996acd22003-04-09 20:59:48 +1000312 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
Ben Lindstrom822b6342002-06-23 21:38:49 +0000313 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100314 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000315}
316
Damien Miller95def091999-11-25 00:26:21 +1100317/*
318 * Generic signal handler for terminating signals in the master daemon.
Damien Miller95def091999-11-25 00:26:21 +1100319 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100320/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000321static void
Damien Miller95def091999-11-25 00:26:21 +1100322sigterm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000323{
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000324 received_sigterm = sig;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000325}
326
Damien Miller95def091999-11-25 00:26:21 +1100327/*
328 * SIGCHLD handler. This is called whenever a child dies. This will then
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000329 * reap any zombies left by exited children.
Damien Miller95def091999-11-25 00:26:21 +1100330 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100331/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000332static void
Damien Miller95def091999-11-25 00:26:21 +1100333main_sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000334{
Damien Miller95def091999-11-25 00:26:21 +1100335 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000336 pid_t pid;
Damien Miller95def091999-11-25 00:26:21 +1100337 int status;
Damien Miller431f66b1999-11-21 18:31:57 +1100338
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000339 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
340 (pid < 0 && errno == EINTR))
Damien Miller95def091999-11-25 00:26:21 +1100341 ;
Damien Miller431f66b1999-11-21 18:31:57 +1100342
Damien Miller95def091999-11-25 00:26:21 +1100343 signal(SIGCHLD, main_sigchld_handler);
344 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000345}
346
Damien Miller95def091999-11-25 00:26:21 +1100347/*
348 * Signal handler for the alarm after the login grace period has expired.
349 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100350/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000351static void
Damien Miller95def091999-11-25 00:26:21 +1100352grace_alarm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000353{
Darren Tuckera8be9e22004-02-06 16:40:27 +1100354 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
355 kill(pmonitor->m_pid, SIGALRM);
356
Damien Miller95def091999-11-25 00:26:21 +1100357 /* Log error and exit. */
Damien Miller99a648e2006-08-19 00:32:20 +1000358 sigdie("Timeout before authentication for %s", get_remote_ipaddr());
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000359}
360
Damien Miller95def091999-11-25 00:26:21 +1100361/*
Damien Miller95def091999-11-25 00:26:21 +1100362 * Signal handler for the key regeneration alarm. Note that this
363 * alarm only occurs in the daemon waiting for connections, and it does not
364 * do anything with the private key or random state before forking.
365 * Thus there should be no concurrency control/asynchronous execution
366 * problems.
367 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000368static void
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000369generate_ephemeral_server_key(void)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100370{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000371 u_int32_t rnd = 0;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000372 int i;
373
Ben Lindstroma3700052001-04-05 23:26:32 +0000374 verbose("Generating %s%d bit RSA key.",
Damien Millerff75ac42001-03-30 10:50:32 +1000375 sensitive_data.server_key ? "new " : "", options.server_key_bits);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100376 if (sensitive_data.server_key != NULL)
377 key_free(sensitive_data.server_key);
Ben Lindstroma3700052001-04-05 23:26:32 +0000378 sensitive_data.server_key = key_generate(KEY_RSA1,
Damien Millerff75ac42001-03-30 10:50:32 +1000379 options.server_key_bits);
380 verbose("RSA key generation complete.");
Ben Lindstromeb648a72001-03-05 06:00:29 +0000381
382 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
383 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000384 rnd = arc4random();
385 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
386 rnd >>= 8;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000387 }
388 arc4random_stir();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100389}
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000390
Damien Millerf0b15df2006-03-26 13:59:20 +1100391/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000392static void
Damien Miller95def091999-11-25 00:26:21 +1100393key_regeneration_alarm(int sig)
394{
395 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000396
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000397 signal(SIGALRM, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +1100398 errno = save_errno;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000399 key_do_regen = 1;
Damien Miller95def091999-11-25 00:26:21 +1100400}
401
Ben Lindstrombba81212001-06-25 05:01:22 +0000402static void
Damien Millerb38eff82000-04-01 11:09:21 +1000403sshd_exchange_identification(int sock_in, int sock_out)
404{
Damien Millereccb9de2005-06-17 12:59:34 +1000405 u_int i;
406 int mismatch;
Damien Millerb38eff82000-04-01 11:09:21 +1000407 int remote_major, remote_minor;
Damien Miller78928792000-04-12 20:17:38 +1000408 int major, minor;
Damien Millerb38eff82000-04-01 11:09:21 +1000409 char *s;
410 char buf[256]; /* Must not be larger than remote_version. */
411 char remote_version[256]; /* Must be at least as big as buf. */
412
Damien Miller78928792000-04-12 20:17:38 +1000413 if ((options.protocol & SSH_PROTO_1) &&
414 (options.protocol & SSH_PROTO_2)) {
415 major = PROTOCOL_MAJOR_1;
416 minor = 99;
417 } else if (options.protocol & SSH_PROTO_2) {
418 major = PROTOCOL_MAJOR_2;
419 minor = PROTOCOL_MINOR_2;
420 } else {
421 major = PROTOCOL_MAJOR_1;
422 minor = PROTOCOL_MINOR_1;
423 }
424 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
Damien Millerb38eff82000-04-01 11:09:21 +1000425 server_version_string = xstrdup(buf);
426
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000427 /* Send our protocol version identification. */
428 if (atomicio(vwrite, sock_out, server_version_string,
429 strlen(server_version_string))
430 != strlen(server_version_string)) {
431 logit("Could not write ident string to %s", get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000432 cleanup_exit(255);
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000433 }
434
435 /* Read other sides version identification. */
436 memset(buf, 0, sizeof(buf));
437 for (i = 0; i < sizeof(buf) - 1; i++) {
438 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
439 logit("Did not receive identification string from %s",
440 get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000441 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000442 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000443 if (buf[i] == '\r') {
444 buf[i] = 0;
445 /* Kludge for F-Secure Macintosh < 1.0.2 */
446 if (i == 12 &&
447 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
Damien Millerb38eff82000-04-01 11:09:21 +1000448 break;
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000449 continue;
Damien Millerb38eff82000-04-01 11:09:21 +1000450 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000451 if (buf[i] == '\n') {
452 buf[i] = 0;
453 break;
454 }
Damien Millerb38eff82000-04-01 11:09:21 +1000455 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000456 buf[sizeof(buf) - 1] = 0;
457 client_version_string = xstrdup(buf);
Damien Millerb38eff82000-04-01 11:09:21 +1000458
459 /*
460 * Check that the versions match. In future this might accept
461 * several versions and set appropriate flags to handle them.
462 */
463 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
464 &remote_major, &remote_minor, remote_version) != 3) {
Damien Miller4af51302000-04-16 11:18:38 +1000465 s = "Protocol mismatch.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000466 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Millerb38eff82000-04-01 11:09:21 +1000467 close(sock_in);
468 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000469 logit("Bad protocol version identification '%.100s' from %s",
Damien Millerb38eff82000-04-01 11:09:21 +1000470 client_version_string, get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000471 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000472 }
473 debug("Client protocol version %d.%d; client software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100474 remote_major, remote_minor, remote_version);
Damien Millerb38eff82000-04-01 11:09:21 +1000475
Damien Millerefb4afe2000-04-12 18:45:05 +1000476 compat_datafellows(remote_version);
477
Damien Millere9264972002-09-30 11:59:21 +1000478 if (datafellows & SSH_BUG_PROBE) {
Damien Miller996acd22003-04-09 20:59:48 +1000479 logit("probed from %s with %s. Don't panic.",
Damien Millere9264972002-09-30 11:59:21 +1000480 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000481 cleanup_exit(255);
Damien Millere9264972002-09-30 11:59:21 +1000482 }
483
Damien Miller27dbe6f2001-03-19 22:36:20 +1100484 if (datafellows & SSH_BUG_SCANNER) {
Damien Miller996acd22003-04-09 20:59:48 +1000485 logit("scanned from %s with %s. Don't panic.",
Damien Miller27dbe6f2001-03-19 22:36:20 +1100486 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000487 cleanup_exit(255);
Damien Miller27dbe6f2001-03-19 22:36:20 +1100488 }
489
Damien Miller78928792000-04-12 20:17:38 +1000490 mismatch = 0;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000491 switch (remote_major) {
Damien Millerb38eff82000-04-01 11:09:21 +1000492 case 1:
Damien Millereba71ba2000-04-29 23:57:08 +1000493 if (remote_minor == 99) {
494 if (options.protocol & SSH_PROTO_2)
495 enable_compat20();
496 else
497 mismatch = 1;
498 break;
499 }
Damien Miller78928792000-04-12 20:17:38 +1000500 if (!(options.protocol & SSH_PROTO_1)) {
501 mismatch = 1;
502 break;
503 }
Damien Millerb38eff82000-04-01 11:09:21 +1000504 if (remote_minor < 3) {
Damien Miller37023962000-07-11 17:31:38 +1000505 packet_disconnect("Your ssh version is too old and "
Damien Millerb38eff82000-04-01 11:09:21 +1000506 "is no longer supported. Please install a newer version.");
507 } else if (remote_minor == 3) {
508 /* note that this disables agent-forwarding */
509 enable_compat13();
510 }
Damien Miller78928792000-04-12 20:17:38 +1000511 break;
Damien Millerefb4afe2000-04-12 18:45:05 +1000512 case 2:
Damien Miller78928792000-04-12 20:17:38 +1000513 if (options.protocol & SSH_PROTO_2) {
Damien Millerefb4afe2000-04-12 18:45:05 +1000514 enable_compat20();
515 break;
516 }
517 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000518 default:
Damien Miller78928792000-04-12 20:17:38 +1000519 mismatch = 1;
Damien Millerb38eff82000-04-01 11:09:21 +1000520 break;
521 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000522 chop(server_version_string);
Damien Miller78928792000-04-12 20:17:38 +1000523 debug("Local version string %.200s", server_version_string);
524
525 if (mismatch) {
526 s = "Protocol major versions differ.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000527 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Miller78928792000-04-12 20:17:38 +1000528 close(sock_in);
529 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000530 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
Damien Miller78928792000-04-12 20:17:38 +1000531 get_remote_ipaddr(),
532 server_version_string, client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000533 cleanup_exit(255);
Damien Miller78928792000-04-12 20:17:38 +1000534 }
Damien Millereba71ba2000-04-29 23:57:08 +1000535}
536
Damien Miller0bc1bd82000-11-13 22:57:25 +1100537/* Destroy the host and server keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +1000538void
539destroy_sensitive_data(void)
540{
Damien Miller0bc1bd82000-11-13 22:57:25 +1100541 int i;
542
543 if (sensitive_data.server_key) {
544 key_free(sensitive_data.server_key);
545 sensitive_data.server_key = NULL;
546 }
Damien Miller9f0f5c62001-12-21 14:45:46 +1100547 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100548 if (sensitive_data.host_keys[i]) {
549 key_free(sensitive_data.host_keys[i]);
550 sensitive_data.host_keys[i] = NULL;
551 }
552 }
553 sensitive_data.ssh1_host_key = NULL;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000554 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100555}
Damien Miller0bc1bd82000-11-13 22:57:25 +1100556
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000557/* Demote private to public keys for network child */
558void
559demote_sensitive_data(void)
560{
561 Key *tmp;
562 int i;
563
564 if (sensitive_data.server_key) {
565 tmp = key_demote(sensitive_data.server_key);
566 key_free(sensitive_data.server_key);
567 sensitive_data.server_key = tmp;
568 }
569
570 for (i = 0; i < options.num_host_key_files; i++) {
571 if (sensitive_data.host_keys[i]) {
572 tmp = key_demote(sensitive_data.host_keys[i]);
573 key_free(sensitive_data.host_keys[i]);
574 sensitive_data.host_keys[i] = tmp;
575 if (tmp->type == KEY_RSA1)
576 sensitive_data.ssh1_host_key = tmp;
577 }
578 }
579
580 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
581}
582
Ben Lindstrom08105192002-03-22 02:50:06 +0000583static void
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000584privsep_preauth_child(void)
585{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000586 u_int32_t rnd[256];
Ben Lindstrom810af962002-07-04 00:11:40 +0000587 gid_t gidset[1];
Damien Miller76e95da2008-03-07 18:31:24 +1100588 u_int i;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000589
590 /* Enable challenge-response authentication for privilege separation */
591 privsep_challenge_enable();
592
Damien Miller76e95da2008-03-07 18:31:24 +1100593 arc4random_stir();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000594 for (i = 0; i < 256; i++)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000595 rnd[i] = arc4random();
596 RAND_seed(rnd, sizeof(rnd));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000597
598 /* Demote the private keys to public keys. */
599 demote_sensitive_data();
600
Ben Lindstroma962c2f2002-07-04 00:14:17 +0000601 /* Change our root directory */
Ben Lindstrom7a7edf72002-03-22 02:42:37 +0000602 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
603 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
604 strerror(errno));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000605 if (chdir("/") == -1)
Ben Lindstrom1ee9ec32002-03-22 03:14:45 +0000606 fatal("chdir(\"/\"): %s", strerror(errno));
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000607
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000608 /* Drop our privileges */
Damien Miller6433df02006-09-07 10:36:43 +1000609 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid,
610 (u_int)privsep_pw->pw_gid);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000611#if 0
Darren Tuckerd5920482004-02-29 20:11:30 +1100612 /* XXX not ready, too heavy after chroot */
Damien Miller6433df02006-09-07 10:36:43 +1000613 do_setusercontext(privsep_pw);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000614#else
Damien Miller6433df02006-09-07 10:36:43 +1000615 gidset[0] = privsep_pw->pw_gid;
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000616 if (setgroups(1, gidset) < 0)
617 fatal("setgroups: %.100s", strerror(errno));
Damien Miller6433df02006-09-07 10:36:43 +1000618 permanently_set_uid(privsep_pw);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000619#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000620}
621
Darren Tucker3e33cec2003-10-02 16:12:36 +1000622static int
623privsep_preauth(Authctxt *authctxt)
Ben Lindstrom943481c2002-03-22 03:43:46 +0000624{
Ben Lindstrom943481c2002-03-22 03:43:46 +0000625 int status;
626 pid_t pid;
627
628 /* Set up unprivileged child process to deal with network data */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000629 pmonitor = monitor_init();
Ben Lindstrom943481c2002-03-22 03:43:46 +0000630 /* Store a pointer to the kex for later rekeying */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000631 pmonitor->m_pkex = &xxx_kex;
Ben Lindstrom943481c2002-03-22 03:43:46 +0000632
633 pid = fork();
634 if (pid == -1) {
635 fatal("fork of unprivileged child failed");
636 } else if (pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000637 debug2("Network child is on pid %ld", (long)pid);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000638
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000639 close(pmonitor->m_recvfd);
Darren Tuckera8be9e22004-02-06 16:40:27 +1100640 pmonitor->m_pid = pid;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000641 monitor_child_preauth(authctxt, pmonitor);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000642 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000643
644 /* Sync memory */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000645 monitor_sync(pmonitor);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000646
647 /* Wait for the child's exit status */
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000648 while (waitpid(pid, &status, 0) < 0)
649 if (errno != EINTR)
650 break;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000651 return (1);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000652 } else {
653 /* child */
654
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000655 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000656
657 /* Demote the child */
658 if (getuid() == 0 || geteuid() == 0)
659 privsep_preauth_child();
Ben Lindstromf90f58d2002-03-26 01:53:03 +0000660 setproctitle("%s", "[net]");
Ben Lindstrom943481c2002-03-22 03:43:46 +0000661 }
Darren Tucker3e33cec2003-10-02 16:12:36 +1000662 return (0);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000663}
664
Ben Lindstrom08105192002-03-22 02:50:06 +0000665static void
Ben Lindstrom943481c2002-03-22 03:43:46 +0000666privsep_postauth(Authctxt *authctxt)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000667{
Damien Miller76e95da2008-03-07 18:31:24 +1100668 u_int32_t rnd[256];
669 u_int i;
670
Tim Rice9dd30812002-07-07 13:43:36 -0700671#ifdef DISABLE_FD_PASSING
Tim Rice8eff3192002-06-25 15:35:15 -0700672 if (1) {
673#else
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000674 if (authctxt->pw->pw_uid == 0 || options.use_login) {
Tim Rice8eff3192002-06-25 15:35:15 -0700675#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000676 /* File descriptor passing is broken or root login */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000677 use_privsep = 0;
Darren Tucker45b01422005-10-03 18:20:00 +1000678 goto skip;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000679 }
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000680
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000681 /* New socket pair */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000682 monitor_reinit(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000683
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000684 pmonitor->m_pid = fork();
685 if (pmonitor->m_pid == -1)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000686 fatal("fork of unprivileged child failed");
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000687 else if (pmonitor->m_pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000688 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000689 close(pmonitor->m_recvfd);
Darren Tuckereb578622004-08-12 23:08:14 +1000690 buffer_clear(&loginmsg);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000691 monitor_child_postauth(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000692
693 /* NEVERREACHED */
694 exit(0);
695 }
696
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000697 close(pmonitor->m_sendfd);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000698
699 /* Demote the private keys to public keys. */
700 demote_sensitive_data();
701
Damien Miller76e95da2008-03-07 18:31:24 +1100702 arc4random_stir();
703 for (i = 0; i < 256; i++)
704 rnd[i] = arc4random();
705 RAND_seed(rnd, sizeof(rnd));
706
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000707 /* Drop privileges */
708 do_setusercontext(authctxt->pw);
709
Darren Tucker45b01422005-10-03 18:20:00 +1000710 skip:
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000711 /* It is safe now to apply the key state */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000712 monitor_apply_keystate(pmonitor);
Damien Miller9786e6e2005-07-26 21:54:56 +1000713
714 /*
715 * Tell the packet layer that authentication was successful, since
716 * this information is not part of the key state.
717 */
718 packet_set_authenticated();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000719}
720
Ben Lindstrombba81212001-06-25 05:01:22 +0000721static char *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100722list_hostkey_types(void)
723{
Damien Miller0e3b8722002-01-22 23:26:38 +1100724 Buffer b;
Damien Millerf58b58c2003-11-17 21:18:23 +1100725 const char *p;
726 char *ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100727 int i;
Damien Miller0e3b8722002-01-22 23:26:38 +1100728
729 buffer_init(&b);
Damien Miller9f0f5c62001-12-21 14:45:46 +1100730 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100731 Key *key = sensitive_data.host_keys[i];
732 if (key == NULL)
733 continue;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000734 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100735 case KEY_RSA:
736 case KEY_DSA:
Damien Miller0e3b8722002-01-22 23:26:38 +1100737 if (buffer_len(&b) > 0)
738 buffer_append(&b, ",", 1);
739 p = key_ssh_name(key);
740 buffer_append(&b, p, strlen(p));
Damien Miller0bc1bd82000-11-13 22:57:25 +1100741 break;
742 }
743 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100744 buffer_append(&b, "\0", 1);
Damien Millerf58b58c2003-11-17 21:18:23 +1100745 ret = xstrdup(buffer_ptr(&b));
Damien Miller0e3b8722002-01-22 23:26:38 +1100746 buffer_free(&b);
Damien Millerf58b58c2003-11-17 21:18:23 +1100747 debug("list_hostkey_types: %s", ret);
748 return ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100749}
750
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000751Key *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100752get_hostkey_by_type(int type)
753{
754 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000755
Damien Miller9f0f5c62001-12-21 14:45:46 +1100756 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100757 Key *key = sensitive_data.host_keys[i];
758 if (key != NULL && key->type == type)
759 return key;
760 }
761 return NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000762}
763
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000764Key *
765get_hostkey_by_index(int ind)
766{
767 if (ind < 0 || ind >= options.num_host_key_files)
768 return (NULL);
769 return (sensitive_data.host_keys[ind]);
770}
771
772int
773get_hostkey_index(Key *key)
774{
775 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000776
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000777 for (i = 0; i < options.num_host_key_files; i++) {
778 if (key == sensitive_data.host_keys[i])
779 return (i);
780 }
781 return (-1);
782}
783
Damien Miller942da032000-08-18 13:59:06 +1000784/*
785 * returns 1 if connection should be dropped, 0 otherwise.
786 * dropping starts at connection #max_startups_begin with a probability
787 * of (max_startups_rate/100). the probability increases linearly until
788 * all connections are dropped for startups > max_startups
789 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000790static int
Damien Miller942da032000-08-18 13:59:06 +1000791drop_connection(int startups)
792{
Darren Tucker178fa662004-11-05 20:09:09 +1100793 int p, r;
Damien Miller942da032000-08-18 13:59:06 +1000794
795 if (startups < options.max_startups_begin)
796 return 0;
797 if (startups >= options.max_startups)
798 return 1;
799 if (options.max_startups_rate == 100)
800 return 1;
801
802 p = 100 - options.max_startups_rate;
803 p *= startups - options.max_startups_begin;
Darren Tucker178fa662004-11-05 20:09:09 +1100804 p /= options.max_startups - options.max_startups_begin;
Damien Miller942da032000-08-18 13:59:06 +1000805 p += options.max_startups_rate;
Darren Tucker178fa662004-11-05 20:09:09 +1100806 r = arc4random() % 100;
Damien Miller942da032000-08-18 13:59:06 +1000807
Darren Tucker3269b132004-11-05 20:20:59 +1100808 debug("drop_connection: p %d, r %d", p, r);
Damien Miller942da032000-08-18 13:59:06 +1000809 return (r < p) ? 1 : 0;
810}
811
Ben Lindstromade03f62001-12-06 18:22:17 +0000812static void
813usage(void)
814{
Damien Miller0c889cd2004-03-22 09:36:00 +1100815 fprintf(stderr, "%s, %s\n",
Damien Miller2aa6d3c2004-09-12 16:53:04 +1000816 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
Damien Millerb4087862004-03-22 09:35:21 +1100817 fprintf(stderr,
818"usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n"
819" [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n"
820 );
Ben Lindstromade03f62001-12-06 18:22:17 +0000821 exit(1);
822}
823
Darren Tucker645ab752004-06-25 13:33:20 +1000824static void
825send_rexec_state(int fd, Buffer *conf)
826{
827 Buffer m;
828
829 debug3("%s: entering fd = %d config len %d", __func__, fd,
830 buffer_len(conf));
831
832 /*
833 * Protocol from reexec master to child:
834 * string configuration
835 * u_int ephemeral_key_follows
836 * bignum e (only if ephemeral_key_follows == 1)
837 * bignum n "
838 * bignum d "
839 * bignum iqmp "
840 * bignum p "
841 * bignum q "
Darren Tuckerc6f82192005-09-27 22:46:32 +1000842 * string rngseed (only if OpenSSL is not self-seeded)
Darren Tucker645ab752004-06-25 13:33:20 +1000843 */
844 buffer_init(&m);
845 buffer_put_cstring(&m, buffer_ptr(conf));
846
Darren Tuckerfc959702004-07-17 16:12:08 +1000847 if (sensitive_data.server_key != NULL &&
Darren Tucker645ab752004-06-25 13:33:20 +1000848 sensitive_data.server_key->type == KEY_RSA1) {
849 buffer_put_int(&m, 1);
850 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
851 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
852 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
853 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
854 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
855 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
856 } else
857 buffer_put_int(&m, 0);
858
Darren Tuckerc6f82192005-09-27 22:46:32 +1000859#ifndef OPENSSL_PRNG_ONLY
860 rexec_send_rng_seed(&m);
861#endif
862
Darren Tucker645ab752004-06-25 13:33:20 +1000863 if (ssh_msg_send(fd, 0, &m) == -1)
864 fatal("%s: ssh_msg_send failed", __func__);
865
866 buffer_free(&m);
867
868 debug3("%s: done", __func__);
869}
870
871static void
872recv_rexec_state(int fd, Buffer *conf)
873{
874 Buffer m;
875 char *cp;
876 u_int len;
877
878 debug3("%s: entering fd = %d", __func__, fd);
879
880 buffer_init(&m);
881
882 if (ssh_msg_recv(fd, &m) == -1)
883 fatal("%s: ssh_msg_recv failed", __func__);
884 if (buffer_get_char(&m) != 0)
885 fatal("%s: rexec version mismatch", __func__);
886
887 cp = buffer_get_string(&m, &len);
888 if (conf != NULL)
889 buffer_append(conf, cp, len + 1);
890 xfree(cp);
891
892 if (buffer_get_int(&m)) {
893 if (sensitive_data.server_key != NULL)
894 key_free(sensitive_data.server_key);
895 sensitive_data.server_key = key_new_private(KEY_RSA1);
896 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
897 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
898 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
899 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
900 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
901 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
902 rsa_generate_additional_parameters(
903 sensitive_data.server_key->rsa);
904 }
Darren Tuckerc6f82192005-09-27 22:46:32 +1000905
906#ifndef OPENSSL_PRNG_ONLY
907 rexec_recv_rng_seed(&m);
908#endif
909
Darren Tucker645ab752004-06-25 13:33:20 +1000910 buffer_free(&m);
911
912 debug3("%s: done", __func__);
913}
914
Damien Millera1f68402006-08-19 00:31:39 +1000915/* Accept a connection from inetd */
916static void
917server_accept_inetd(int *sock_in, int *sock_out)
918{
919 int fd;
920
921 startup_pipe = -1;
922 if (rexeced_flag) {
923 close(REEXEC_CONFIG_PASS_FD);
924 *sock_in = *sock_out = dup(STDIN_FILENO);
925 if (!debug_flag) {
926 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
927 close(REEXEC_STARTUP_PIPE_FD);
928 }
929 } else {
930 *sock_in = dup(STDIN_FILENO);
931 *sock_out = dup(STDOUT_FILENO);
932 }
933 /*
934 * We intentionally do not close the descriptors 0, 1, and 2
935 * as our code for setting the descriptors won't work if
936 * ttyfd happens to be one of those.
937 */
938 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
939 dup2(fd, STDIN_FILENO);
940 dup2(fd, STDOUT_FILENO);
941 if (fd > STDOUT_FILENO)
942 close(fd);
943 }
944 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
945}
946
947/*
948 * Listen for TCP connections
949 */
950static void
951server_listen(void)
952{
953 int ret, listen_sock, on = 1;
954 struct addrinfo *ai;
955 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
956
957 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
958 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
959 continue;
960 if (num_listen_socks >= MAX_LISTEN_SOCKS)
961 fatal("Too many listen sockets. "
962 "Enlarge MAX_LISTEN_SOCKS");
963 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
964 ntop, sizeof(ntop), strport, sizeof(strport),
965 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
966 error("getnameinfo failed: %.100s",
Darren Tucker4abde772007-12-29 02:43:51 +1100967 ssh_gai_strerror(ret));
Damien Millera1f68402006-08-19 00:31:39 +1000968 continue;
969 }
970 /* Create socket for listening. */
971 listen_sock = socket(ai->ai_family, ai->ai_socktype,
972 ai->ai_protocol);
973 if (listen_sock < 0) {
974 /* kernel may not support ipv6 */
975 verbose("socket: %.100s", strerror(errno));
976 continue;
977 }
978 if (set_nonblock(listen_sock) == -1) {
979 close(listen_sock);
980 continue;
981 }
982 /*
983 * Set socket options.
984 * Allow local port reuse in TIME_WAIT.
985 */
986 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
987 &on, sizeof(on)) == -1)
988 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
989
Damien Miller49d2a282008-01-20 08:56:00 +1100990#ifdef IPV6_V6ONLY
991 /* Only communicate in IPv6 over AF_INET6 sockets. */
992 if (ai->ai_family == AF_INET6) {
993 if (setsockopt(listen_sock, IPPROTO_IPV6, IPV6_V6ONLY,
994 &on, sizeof(on)) == -1)
995 error("setsockopt IPV6_V6ONLY: %s",
996 strerror(errno));
997 }
998#endif
999
Damien Millera1f68402006-08-19 00:31:39 +10001000 debug("Bind to port %s on %s.", strport, ntop);
1001
1002 /* Bind the socket to the desired port. */
1003 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1004 error("Bind to port %s on %s failed: %.200s.",
1005 strport, ntop, strerror(errno));
1006 close(listen_sock);
1007 continue;
1008 }
1009 listen_socks[num_listen_socks] = listen_sock;
1010 num_listen_socks++;
1011
1012 /* Start listening on the port. */
1013 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1014 fatal("listen on [%s]:%s: %.100s",
1015 ntop, strport, strerror(errno));
1016 logit("Server listening on %s port %s.", ntop, strport);
1017 }
1018 freeaddrinfo(options.listen_addrs);
1019
1020 if (!num_listen_socks)
1021 fatal("Cannot bind any address.");
1022}
1023
1024/*
1025 * The main TCP accept loop. Note that, for the non-debug case, returns
1026 * from this function are in a forked subprocess.
1027 */
1028static void
1029server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1030{
1031 fd_set *fdset;
1032 int i, j, ret, maxfd;
1033 int key_used = 0, startups = 0;
1034 int startup_p[2] = { -1 , -1 };
1035 struct sockaddr_storage from;
1036 socklen_t fromlen;
1037 pid_t pid;
1038
1039 /* setup fd set for accept */
1040 fdset = NULL;
1041 maxfd = 0;
1042 for (i = 0; i < num_listen_socks; i++)
1043 if (listen_socks[i] > maxfd)
1044 maxfd = listen_socks[i];
1045 /* pipes connected to unauthenticated childs */
1046 startup_pipes = xcalloc(options.max_startups, sizeof(int));
1047 for (i = 0; i < options.max_startups; i++)
1048 startup_pipes[i] = -1;
1049
1050 /*
1051 * Stay listening for connections until the system crashes or
1052 * the daemon is killed with a signal.
1053 */
1054 for (;;) {
1055 if (received_sighup)
1056 sighup_restart();
1057 if (fdset != NULL)
1058 xfree(fdset);
1059 fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS),
1060 sizeof(fd_mask));
1061
1062 for (i = 0; i < num_listen_socks; i++)
1063 FD_SET(listen_socks[i], fdset);
1064 for (i = 0; i < options.max_startups; i++)
1065 if (startup_pipes[i] != -1)
1066 FD_SET(startup_pipes[i], fdset);
1067
1068 /* Wait in select until there is a connection. */
1069 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1070 if (ret < 0 && errno != EINTR)
1071 error("select: %.100s", strerror(errno));
1072 if (received_sigterm) {
1073 logit("Received signal %d; terminating.",
1074 (int) received_sigterm);
1075 close_listen_socks();
1076 unlink(options.pid_file);
1077 exit(255);
1078 }
1079 if (key_used && key_do_regen) {
1080 generate_ephemeral_server_key();
1081 key_used = 0;
1082 key_do_regen = 0;
1083 }
1084 if (ret < 0)
1085 continue;
1086
1087 for (i = 0; i < options.max_startups; i++)
1088 if (startup_pipes[i] != -1 &&
1089 FD_ISSET(startup_pipes[i], fdset)) {
1090 /*
1091 * the read end of the pipe is ready
1092 * if the child has closed the pipe
1093 * after successful authentication
1094 * or if the child has died
1095 */
1096 close(startup_pipes[i]);
1097 startup_pipes[i] = -1;
1098 startups--;
1099 }
1100 for (i = 0; i < num_listen_socks; i++) {
1101 if (!FD_ISSET(listen_socks[i], fdset))
1102 continue;
1103 fromlen = sizeof(from);
1104 *newsock = accept(listen_socks[i],
1105 (struct sockaddr *)&from, &fromlen);
1106 if (*newsock < 0) {
1107 if (errno != EINTR && errno != EWOULDBLOCK)
1108 error("accept: %.100s", strerror(errno));
1109 continue;
1110 }
1111 if (unset_nonblock(*newsock) == -1) {
1112 close(*newsock);
1113 continue;
1114 }
1115 if (drop_connection(startups) == 1) {
1116 debug("drop connection #%d", startups);
1117 close(*newsock);
1118 continue;
1119 }
1120 if (pipe(startup_p) == -1) {
1121 close(*newsock);
1122 continue;
1123 }
1124
1125 if (rexec_flag && socketpair(AF_UNIX,
1126 SOCK_STREAM, 0, config_s) == -1) {
1127 error("reexec socketpair: %s",
1128 strerror(errno));
1129 close(*newsock);
1130 close(startup_p[0]);
1131 close(startup_p[1]);
1132 continue;
1133 }
1134
1135 for (j = 0; j < options.max_startups; j++)
1136 if (startup_pipes[j] == -1) {
1137 startup_pipes[j] = startup_p[0];
1138 if (maxfd < startup_p[0])
1139 maxfd = startup_p[0];
1140 startups++;
1141 break;
1142 }
1143
1144 /*
1145 * Got connection. Fork a child to handle it, unless
1146 * we are in debugging mode.
1147 */
1148 if (debug_flag) {
1149 /*
1150 * In debugging mode. Close the listening
1151 * socket, and start processing the
1152 * connection without forking.
1153 */
1154 debug("Server will not fork when running in debugging mode.");
1155 close_listen_socks();
1156 *sock_in = *newsock;
1157 *sock_out = *newsock;
1158 close(startup_p[0]);
1159 close(startup_p[1]);
1160 startup_pipe = -1;
1161 pid = getpid();
1162 if (rexec_flag) {
1163 send_rexec_state(config_s[0],
1164 &cfg);
1165 close(config_s[0]);
1166 }
1167 break;
1168 }
1169
1170 /*
1171 * Normal production daemon. Fork, and have
1172 * the child process the connection. The
1173 * parent continues listening.
1174 */
Damien Miller1b06dc32006-08-31 03:24:41 +10001175 platform_pre_fork();
Damien Millera1f68402006-08-19 00:31:39 +10001176 if ((pid = fork()) == 0) {
1177 /*
1178 * Child. Close the listening and
1179 * max_startup sockets. Start using
1180 * the accepted socket. Reinitialize
1181 * logging (since our pid has changed).
1182 * We break out of the loop to handle
1183 * the connection.
1184 */
Damien Miller1b06dc32006-08-31 03:24:41 +10001185 platform_post_fork_child();
Damien Millera1f68402006-08-19 00:31:39 +10001186 startup_pipe = startup_p[1];
1187 close_startup_pipes();
1188 close_listen_socks();
1189 *sock_in = *newsock;
1190 *sock_out = *newsock;
1191 log_init(__progname,
1192 options.log_level,
1193 options.log_facility,
1194 log_stderr);
1195 if (rexec_flag)
1196 close(config_s[0]);
1197 break;
1198 }
1199
1200 /* Parent. Stay in the loop. */
Damien Miller1b06dc32006-08-31 03:24:41 +10001201 platform_post_fork_parent(pid);
Damien Millera1f68402006-08-19 00:31:39 +10001202 if (pid < 0)
1203 error("fork: %.100s", strerror(errno));
1204 else
1205 debug("Forked child %ld.", (long)pid);
1206
1207 close(startup_p[1]);
1208
1209 if (rexec_flag) {
1210 send_rexec_state(config_s[0], &cfg);
1211 close(config_s[0]);
1212 close(config_s[1]);
1213 }
1214
1215 /*
1216 * Mark that the key has been used (it
1217 * was "given" to the child).
1218 */
1219 if ((options.protocol & SSH_PROTO_1) &&
1220 key_used == 0) {
1221 /* Schedule server key regeneration alarm. */
1222 signal(SIGALRM, key_regeneration_alarm);
1223 alarm(options.key_regeneration_time);
1224 key_used = 1;
1225 }
1226
1227 close(*newsock);
1228
1229 /*
1230 * Ensure that our random state differs
1231 * from that of the child
1232 */
1233 arc4random_stir();
1234 }
1235
1236 /* child process check (or debug mode) */
1237 if (num_listen_socks < 0)
1238 break;
1239 }
1240}
1241
1242
Damien Miller95def091999-11-25 00:26:21 +11001243/*
1244 * Main program for the daemon.
1245 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001246int
1247main(int ac, char **av)
1248{
Damien Miller95def091999-11-25 00:26:21 +11001249 extern char *optarg;
1250 extern int optind;
Damien Millera1f68402006-08-19 00:31:39 +10001251 int opt, i, on = 1;
Damien Miller386c6a22004-06-30 22:40:20 +10001252 int sock_in = -1, sock_out = -1, newsock = -1;
Damien Miller95def091999-11-25 00:26:21 +11001253 const char *remote_ip;
1254 int remote_port;
Damien Millerb9997192003-12-17 16:29:22 +11001255 char *line;
Damien Millera1f68402006-08-19 00:31:39 +10001256 int config_s[2] = { -1 , -1 };
Ben Lindstromd0fca422001-03-26 13:44:06 +00001257 Key *key;
Darren Tucker3e33cec2003-10-02 16:12:36 +10001258 Authctxt *authctxt;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001259
Kevin Steves0ea1d9d2002-04-25 18:17:04 +00001260#ifdef HAVE_SECUREWARE
1261 (void)set_auth_parameters(ac, av);
1262#endif
Damien Miller59d3d5b2003-08-22 09:34:41 +10001263 __progname = ssh_get_progname(av[0]);
Damien Millerf9b625c2000-07-09 22:42:32 +10001264 init_rng();
1265
Damien Millera8ed44b2003-01-10 09:53:12 +11001266 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
Damien Millerb8c656e2000-06-28 15:22:41 +10001267 saved_argc = ac;
Darren Tucker17c5d032004-06-25 14:22:23 +10001268 rexec_argc = ac;
Darren Tuckerd8093e42006-05-04 16:24:34 +10001269 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
Damien Millera8ed44b2003-01-10 09:53:12 +11001270 for (i = 0; i < ac; i++)
1271 saved_argv[i] = xstrdup(av[i]);
Damien Miller04cb5362003-05-15 21:29:10 +10001272 saved_argv[i] = NULL;
Damien Millera8ed44b2003-01-10 09:53:12 +11001273
1274#ifndef HAVE_SETPROCTITLE
1275 /* Prepare for later setproctitle emulation */
1276 compat_init_setproctitle(ac, av);
Damien Millerf2e3e9d2003-06-02 12:15:54 +10001277 av = saved_argv;
Damien Millera8ed44b2003-01-10 09:53:12 +11001278#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001279
Damien Millerbfba3542004-03-22 09:29:57 +11001280 if (geteuid() == 0 && setgroups(0, NULL) == -1)
1281 debug("setgroups(): %.200s", strerror(errno));
1282
Darren Tuckerce321d82005-10-03 18:11:24 +10001283 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1284 sanitise_stdfd();
1285
Damien Miller95def091999-11-25 00:26:21 +11001286 /* Initialize configuration options to their default values. */
1287 initialize_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001288
Damien Miller95def091999-11-25 00:26:21 +11001289 /* Parse command-line arguments. */
Darren Tucker645ab752004-06-25 13:33:20 +10001290 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) {
Damien Miller95def091999-11-25 00:26:21 +11001291 switch (opt) {
Damien Miller34132e52000-01-14 15:45:46 +11001292 case '4':
Darren Tucker0f383232005-01-20 10:57:56 +11001293 options.address_family = AF_INET;
Damien Miller34132e52000-01-14 15:45:46 +11001294 break;
1295 case '6':
Darren Tucker0f383232005-01-20 10:57:56 +11001296 options.address_family = AF_INET6;
Damien Miller34132e52000-01-14 15:45:46 +11001297 break;
Damien Miller95def091999-11-25 00:26:21 +11001298 case 'f':
1299 config_file_name = optarg;
1300 break;
1301 case 'd':
Darren Tuckere98dfa32003-07-19 19:54:31 +10001302 if (debug_flag == 0) {
Damien Millere4340be2000-09-16 13:29:08 +11001303 debug_flag = 1;
1304 options.log_level = SYSLOG_LEVEL_DEBUG1;
Darren Tuckere98dfa32003-07-19 19:54:31 +10001305 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
Damien Millere4340be2000-09-16 13:29:08 +11001306 options.log_level++;
Damien Miller95def091999-11-25 00:26:21 +11001307 break;
Ben Lindstromc72745a2000-12-02 19:03:54 +00001308 case 'D':
1309 no_daemon_flag = 1;
1310 break;
Ben Lindstrom9fce9f02001-04-11 23:10:09 +00001311 case 'e':
1312 log_stderr = 1;
1313 break;
Damien Miller95def091999-11-25 00:26:21 +11001314 case 'i':
1315 inetd_flag = 1;
1316 break;
Darren Tucker645ab752004-06-25 13:33:20 +10001317 case 'r':
1318 rexec_flag = 0;
1319 break;
1320 case 'R':
1321 rexeced_flag = 1;
1322 inetd_flag = 1;
1323 break;
Damien Miller95def091999-11-25 00:26:21 +11001324 case 'Q':
Ben Lindstromd5390202001-01-29 08:07:43 +00001325 /* ignored */
Damien Miller95def091999-11-25 00:26:21 +11001326 break;
1327 case 'q':
1328 options.log_level = SYSLOG_LEVEL_QUIET;
1329 break;
1330 case 'b':
Damien Millerf0b15df2006-03-26 13:59:20 +11001331 options.server_key_bits = (int)strtonum(optarg, 256,
1332 32768, NULL);
Damien Miller95def091999-11-25 00:26:21 +11001333 break;
1334 case 'p':
Damien Miller34132e52000-01-14 15:45:46 +11001335 options.ports_from_cmdline = 1;
Damien Millere4340be2000-09-16 13:29:08 +11001336 if (options.num_ports >= MAX_PORTS) {
1337 fprintf(stderr, "too many ports.\n");
1338 exit(1);
1339 }
Ben Lindstrom19066a12001-04-12 23:39:26 +00001340 options.ports[options.num_ports++] = a2port(optarg);
1341 if (options.ports[options.num_ports-1] == 0) {
1342 fprintf(stderr, "Bad port number.\n");
1343 exit(1);
1344 }
Damien Miller95def091999-11-25 00:26:21 +11001345 break;
1346 case 'g':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +00001347 if ((options.login_grace_time = convtime(optarg)) == -1) {
1348 fprintf(stderr, "Invalid login grace time.\n");
1349 exit(1);
1350 }
Damien Miller95def091999-11-25 00:26:21 +11001351 break;
1352 case 'k':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +00001353 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
1354 fprintf(stderr, "Invalid key regeneration interval.\n");
1355 exit(1);
1356 }
Damien Miller95def091999-11-25 00:26:21 +11001357 break;
1358 case 'h':
Damien Miller0bc1bd82000-11-13 22:57:25 +11001359 if (options.num_host_key_files >= MAX_HOSTKEYS) {
1360 fprintf(stderr, "too many host keys.\n");
1361 exit(1);
1362 }
1363 options.host_key_files[options.num_host_key_files++] = optarg;
Damien Miller95def091999-11-25 00:26:21 +11001364 break;
Ben Lindstrom794325a2001-08-06 21:09:07 +00001365 case 't':
1366 test_flag = 1;
1367 break;
Damien Miller942da032000-08-18 13:59:06 +10001368 case 'u':
Damien Millerf0b15df2006-03-26 13:59:20 +11001369 utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL);
Ben Lindstrom41daec72002-07-23 21:15:13 +00001370 if (utmp_len > MAXHOSTNAMELEN) {
1371 fprintf(stderr, "Invalid utmp length.\n");
1372 exit(1);
1373 }
Damien Miller942da032000-08-18 13:59:06 +10001374 break;
Ben Lindstromade03f62001-12-06 18:22:17 +00001375 case 'o':
Damien Millerb9997192003-12-17 16:29:22 +11001376 line = xstrdup(optarg);
1377 if (process_server_config_line(&options, line,
Darren Tucker45150472006-07-12 22:34:17 +10001378 "command-line", 0, NULL, NULL, NULL, NULL) != 0)
Damien Miller9f0f5c62001-12-21 14:45:46 +11001379 exit(1);
Damien Millerb9997192003-12-17 16:29:22 +11001380 xfree(line);
Ben Lindstromade03f62001-12-06 18:22:17 +00001381 break;
Damien Miller95def091999-11-25 00:26:21 +11001382 case '?':
1383 default:
Ben Lindstromade03f62001-12-06 18:22:17 +00001384 usage();
1385 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001386 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001387 }
Darren Tucker645ab752004-06-25 13:33:20 +10001388 if (rexeced_flag || inetd_flag)
1389 rexec_flag = 0;
Damien Miller2ee0c432008-03-07 18:31:47 +11001390 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
Darren Tucker645ab752004-06-25 13:33:20 +10001391 fatal("sshd re-exec requires execution with an absolute path");
1392 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001393 closefrom(REEXEC_MIN_FREE_FD);
1394 else
1395 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001396
Ben Lindstrom425fb022001-03-29 00:31:20 +00001397 SSLeay_add_all_algorithms();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001398
Damien Miller34132e52000-01-14 15:45:46 +11001399 /*
1400 * Force logging to stderr until we have loaded the private host
1401 * key (unless started from inetd)
1402 */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001403 log_init(__progname,
Damien Miller5aa5d782002-02-08 22:01:54 +11001404 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1405 SYSLOG_LEVEL_INFO : options.log_level,
1406 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1407 SYSLOG_FACILITY_AUTH : options.log_facility,
Ben Lindstromc2faa4a2002-11-09 15:50:03 +00001408 log_stderr || !inetd_flag);
Damien Miller34132e52000-01-14 15:45:46 +11001409
Darren Tucker86c093d2004-03-08 22:59:03 +11001410 /*
1411 * Unset KRB5CCNAME, otherwise the user's session may inherit it from
1412 * root's environment
Damien Miller94cf4c82005-07-17 17:04:47 +10001413 */
Darren Tucker9dc6c7d2005-02-02 18:30:33 +11001414 if (getenv("KRB5CCNAME") != NULL)
1415 unsetenv("KRB5CCNAME");
1416
Tim Rice81ed5182002-09-25 17:38:46 -07001417#ifdef _UNICOS
Darren Tucker12984962004-05-24 13:37:13 +10001418 /* Cray can define user privs drop all privs now!
Ben Lindstrom6db66ff2001-08-06 23:29:16 +00001419 * Not needed on PRIV_SU systems!
1420 */
1421 drop_cray_privs();
1422#endif
1423
Darren Tucker645ab752004-06-25 13:33:20 +10001424 sensitive_data.server_key = NULL;
1425 sensitive_data.ssh1_host_key = NULL;
1426 sensitive_data.have_ssh1_key = 0;
1427 sensitive_data.have_ssh2_key = 0;
1428
1429 /* Fetch our configuration */
1430 buffer_init(&cfg);
1431 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001432 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
Darren Tucker645ab752004-06-25 13:33:20 +10001433 else
1434 load_server_config(config_file_name, &cfg);
1435
Darren Tucker45150472006-07-12 22:34:17 +10001436 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1437 &cfg, NULL, NULL, NULL);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001438
Darren Tuckerc6f82192005-09-27 22:46:32 +10001439 seed_rng();
1440
Damien Miller95def091999-11-25 00:26:21 +11001441 /* Fill in default values for those options not explicitly set. */
1442 fill_default_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001443
Darren Tucker97b1bb52007-03-21 20:38:53 +11001444 /* challenge-response is implemented via keyboard interactive */
1445 if (options.challenge_response_authentication)
1446 options.kbd_interactive_authentication = 1;
1447
Darren Tucker0f383232005-01-20 10:57:56 +11001448 /* set default channel AF */
1449 channel_set_af(options.address_family);
1450
Damien Miller95def091999-11-25 00:26:21 +11001451 /* Check that there are no remaining arguments. */
1452 if (optind < ac) {
1453 fprintf(stderr, "Extra argument %s.\n", av[optind]);
1454 exit(1);
1455 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001456
Damien Miller2aa6d3c2004-09-12 16:53:04 +10001457 debug("sshd version %.100s", SSH_RELEASE);
Damien Miller2ccf6611999-11-15 15:25:10 +11001458
Darren Tuckerdf0e4382006-11-07 11:28:40 +11001459 /* Store privilege separation user for later use if required. */
1460 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
1461 if (use_privsep || options.kerberos_authentication)
1462 fatal("Privilege separation user %s does not exist",
1463 SSH_PRIVSEP_USER);
1464 } else {
1465 memset(privsep_pw->pw_passwd, 0, strlen(privsep_pw->pw_passwd));
1466 privsep_pw = pwcopy(privsep_pw);
1467 xfree(privsep_pw->pw_passwd);
1468 privsep_pw->pw_passwd = xstrdup("*");
1469 }
Damien Miller6433df02006-09-07 10:36:43 +10001470 endpwent();
1471
Damien Miller0bc1bd82000-11-13 22:57:25 +11001472 /* load private host keys */
Damien Miller07d86be2006-03-26 14:19:21 +11001473 sensitive_data.host_keys = xcalloc(options.num_host_key_files,
Ben Lindstroma962c2f2002-07-04 00:14:17 +00001474 sizeof(Key *));
Damien Miller9f0f5c62001-12-21 14:45:46 +11001475 for (i = 0; i < options.num_host_key_files; i++)
Ben Lindstrom46c16222000-12-22 01:43:59 +00001476 sensitive_data.host_keys[i] = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +10001477
Damien Miller9f0f5c62001-12-21 14:45:46 +11001478 for (i = 0; i < options.num_host_key_files; i++) {
Ben Lindstromd0fca422001-03-26 13:44:06 +00001479 key = key_load_private(options.host_key_files[i], "", NULL);
1480 sensitive_data.host_keys[i] = key;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001481 if (key == NULL) {
Ben Lindstrom15f33862001-04-16 02:00:02 +00001482 error("Could not load host key: %s",
1483 options.host_key_files[i]);
Ben Lindstromd0fca422001-03-26 13:44:06 +00001484 sensitive_data.host_keys[i] = NULL;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001485 continue;
1486 }
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +00001487 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +11001488 case KEY_RSA1:
1489 sensitive_data.ssh1_host_key = key;
1490 sensitive_data.have_ssh1_key = 1;
1491 break;
1492 case KEY_RSA:
1493 case KEY_DSA:
1494 sensitive_data.have_ssh2_key = 1;
1495 break;
1496 }
Ben Lindstromd0fca422001-03-26 13:44:06 +00001497 debug("private host key: #%d type %d %s", i, key->type,
1498 key_type(key));
Damien Miller0bc1bd82000-11-13 22:57:25 +11001499 }
1500 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001501 logit("Disabling protocol version 1. Could not load host key");
Damien Millereba71ba2000-04-29 23:57:08 +10001502 options.protocol &= ~SSH_PROTO_1;
1503 }
Damien Miller0bc1bd82000-11-13 22:57:25 +11001504 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001505 logit("Disabling protocol version 2. Could not load host key");
Damien Miller0bc1bd82000-11-13 22:57:25 +11001506 options.protocol &= ~SSH_PROTO_2;
Damien Millereba71ba2000-04-29 23:57:08 +10001507 }
Kevin Stevesadf74cd2001-02-05 14:22:50 +00001508 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
Damien Miller996acd22003-04-09 20:59:48 +10001509 logit("sshd: no hostkeys available -- exiting.");
Damien Miller95def091999-11-25 00:26:21 +11001510 exit(1);
1511 }
Damien Miller95def091999-11-25 00:26:21 +11001512
Damien Millereba71ba2000-04-29 23:57:08 +10001513 /* Check certain values for sanity. */
1514 if (options.protocol & SSH_PROTO_1) {
1515 if (options.server_key_bits < 512 ||
1516 options.server_key_bits > 32768) {
1517 fprintf(stderr, "Bad server key size.\n");
1518 exit(1);
1519 }
1520 /*
1521 * Check that server and host key lengths differ sufficiently. This
1522 * is necessary to make double encryption work with rsaref. Oh, I
1523 * hate software patents. I dont know if this can go? Niels
1524 */
1525 if (options.server_key_bits >
Ben Lindstrom822b6342002-06-23 21:38:49 +00001526 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1527 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1528 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1529 SSH_KEY_BITS_RESERVED) {
Damien Millereba71ba2000-04-29 23:57:08 +10001530 options.server_key_bits =
Ben Lindstrom822b6342002-06-23 21:38:49 +00001531 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1532 SSH_KEY_BITS_RESERVED;
Damien Millereba71ba2000-04-29 23:57:08 +10001533 debug("Forcing server key to %d bits to make it differ from host key.",
1534 options.server_key_bits);
1535 }
1536 }
1537
Ben Lindstroma26ea632002-06-06 20:46:25 +00001538 if (use_privsep) {
Ben Lindstroma26ea632002-06-06 20:46:25 +00001539 struct stat st;
1540
Ben Lindstroma26ea632002-06-06 20:46:25 +00001541 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1542 (S_ISDIR(st.st_mode) == 0))
1543 fatal("Missing privilege separation directory: %s",
1544 _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstrom59627352002-06-27 18:02:21 +00001545
1546#ifdef HAVE_CYGWIN
1547 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1548 (st.st_uid != getuid () ||
1549 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1550#else
Ben Lindstrom2dfacb32002-06-23 00:33:47 +00001551 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
Ben Lindstrom59627352002-06-27 18:02:21 +00001552#endif
Damien Miller180fc5b2003-02-24 11:50:18 +11001553 fatal("%s must be owned by root and not group or "
1554 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstroma26ea632002-06-06 20:46:25 +00001555 }
1556
Ben Lindstrom794325a2001-08-06 21:09:07 +00001557 /* Configuration looks good, so exit if in test mode. */
1558 if (test_flag)
1559 exit(0);
1560
Damien Miller87aea252002-05-10 12:20:24 +10001561 /*
1562 * Clear out any supplemental groups we may have inherited. This
1563 * prevents inadvertent creation of files with bad modes (in the
Damien Millera8e06ce2003-11-21 23:48:55 +11001564 * portable version at least, it's certainly possible for PAM
1565 * to create a file, and we can't control the code in every
Damien Miller87aea252002-05-10 12:20:24 +10001566 * module which might be used).
1567 */
1568 if (setgroups(0, NULL) < 0)
1569 debug("setgroups() failed: %.200s", strerror(errno));
1570
Darren Tucker645ab752004-06-25 13:33:20 +10001571 if (rexec_flag) {
Damien Miller07d86be2006-03-26 14:19:21 +11001572 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
Darren Tucker645ab752004-06-25 13:33:20 +10001573 for (i = 0; i < rexec_argc; i++) {
1574 debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1575 rexec_argv[i] = saved_argv[i];
1576 }
1577 rexec_argv[rexec_argc] = "-R";
1578 rexec_argv[rexec_argc + 1] = NULL;
1579 }
1580
Damien Millereba71ba2000-04-29 23:57:08 +10001581 /* Initialize the log (it is reinitialized below in case we forked). */
Darren Tuckerea7c8122005-01-20 11:03:08 +11001582 if (debug_flag && (!inetd_flag || rexeced_flag))
Damien Miller95def091999-11-25 00:26:21 +11001583 log_stderr = 1;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001584 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001585
Damien Millereba71ba2000-04-29 23:57:08 +10001586 /*
1587 * If not in debugging mode, and not started from inetd, disconnect
1588 * from the controlling terminal, and fork. The original process
1589 * exits.
1590 */
Ben Lindstromc72745a2000-12-02 19:03:54 +00001591 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
Damien Miller95def091999-11-25 00:26:21 +11001592#ifdef TIOCNOTTY
1593 int fd;
1594#endif /* TIOCNOTTY */
1595 if (daemon(0, 0) < 0)
1596 fatal("daemon() failed: %.200s", strerror(errno));
1597
1598 /* Disconnect from the controlling tty. */
1599#ifdef TIOCNOTTY
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001600 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +11001601 if (fd >= 0) {
1602 (void) ioctl(fd, TIOCNOTTY, NULL);
1603 close(fd);
1604 }
1605#endif /* TIOCNOTTY */
1606 }
1607 /* Reinitialize the log (because of the fork above). */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001608 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001609
Damien Miller95def091999-11-25 00:26:21 +11001610 /* Initialize the random number generator. */
1611 arc4random_stir();
1612
1613 /* Chdir to the root directory so that the current disk can be
1614 unmounted if desired. */
1615 chdir("/");
Damien Miller9f0f5c62001-12-21 14:45:46 +11001616
Ben Lindstromde71cda2001-03-24 00:43:26 +00001617 /* ignore SIGPIPE */
1618 signal(SIGPIPE, SIG_IGN);
Damien Miller95def091999-11-25 00:26:21 +11001619
Damien Millera1f68402006-08-19 00:31:39 +10001620 /* Get a connection, either from inetd or a listening TCP socket */
Damien Miller95def091999-11-25 00:26:21 +11001621 if (inetd_flag) {
Damien Millera1f68402006-08-19 00:31:39 +10001622 server_accept_inetd(&sock_in, &sock_out);
Damien Miller95def091999-11-25 00:26:21 +11001623 } else {
Damien Millera1f68402006-08-19 00:31:39 +10001624 server_listen();
Damien Miller34132e52000-01-14 15:45:46 +11001625
Ben Lindstrom98097862001-06-25 05:10:20 +00001626 if (options.protocol & SSH_PROTO_1)
1627 generate_ephemeral_server_key();
1628
Ben Lindstrom98097862001-06-25 05:10:20 +00001629 signal(SIGHUP, sighup_handler);
Damien Millera1f68402006-08-19 00:31:39 +10001630 signal(SIGCHLD, main_sigchld_handler);
Ben Lindstrom98097862001-06-25 05:10:20 +00001631 signal(SIGTERM, sigterm_handler);
1632 signal(SIGQUIT, sigterm_handler);
1633
Damien Millera1f68402006-08-19 00:31:39 +10001634 /*
1635 * Write out the pid file after the sigterm handler
1636 * is setup and the listen sockets are bound
1637 */
Damien Miller95def091999-11-25 00:26:21 +11001638 if (!debug_flag) {
Damien Millera1f68402006-08-19 00:31:39 +10001639 FILE *f = fopen(options.pid_file, "w");
1640
Darren Tuckere5327042003-07-03 13:40:44 +10001641 if (f == NULL) {
1642 error("Couldn't create pid file \"%s\": %s",
1643 options.pid_file, strerror(errno));
1644 } else {
Ben Lindstromce0f6342002-06-11 16:42:49 +00001645 fprintf(f, "%ld\n", (long) getpid());
Damien Miller95def091999-11-25 00:26:21 +11001646 fclose(f);
1647 }
1648 }
Damien Miller95def091999-11-25 00:26:21 +11001649
Damien Millera1f68402006-08-19 00:31:39 +10001650 /* Accept a connection and return in a forked child */
1651 server_accept_loop(&sock_in, &sock_out,
1652 &newsock, config_s);
Damien Miller95def091999-11-25 00:26:21 +11001653 }
1654
1655 /* This is the child processing a new connection. */
Damien Miller57aae982004-03-08 23:11:25 +11001656 setproctitle("%s", "[accepted]");
Damien Miller95def091999-11-25 00:26:21 +11001657
Darren Tucker6832b832004-08-12 22:36:51 +10001658 /*
1659 * Create a new session and process group since the 4.4BSD
1660 * setlogin() affects the entire process group. We don't
1661 * want the child to be able to affect the parent.
1662 */
1663#if !defined(SSHD_ACQUIRES_CTTY)
1664 /*
1665 * If setsid is called, on some platforms sshd will later acquire a
1666 * controlling terminal which will result in "could not set
1667 * controlling tty" errors.
1668 */
1669 if (!debug_flag && !inetd_flag && setsid() < 0)
1670 error("setsid: %.100s", strerror(errno));
1671#endif
1672
Darren Tucker645ab752004-06-25 13:33:20 +10001673 if (rexec_flag) {
1674 int fd;
1675
Damien Miller035a5b42004-06-26 08:16:31 +10001676 debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1677 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001678 dup2(newsock, STDIN_FILENO);
1679 dup2(STDIN_FILENO, STDOUT_FILENO);
1680 if (startup_pipe == -1)
Damien Miller035a5b42004-06-26 08:16:31 +10001681 close(REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001682 else
Damien Miller035a5b42004-06-26 08:16:31 +10001683 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001684
Damien Miller035a5b42004-06-26 08:16:31 +10001685 dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001686 close(config_s[1]);
Darren Tuckerd8835932004-08-12 22:42:29 +10001687 if (startup_pipe != -1)
1688 close(startup_pipe);
Damien Miller035a5b42004-06-26 08:16:31 +10001689
Darren Tucker645ab752004-06-25 13:33:20 +10001690 execv(rexec_argv[0], rexec_argv);
1691
1692 /* Reexec has failed, fall back and continue */
1693 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
Damien Miller035a5b42004-06-26 08:16:31 +10001694 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
Darren Tucker645ab752004-06-25 13:33:20 +10001695 log_init(__progname, options.log_level,
1696 options.log_facility, log_stderr);
1697
1698 /* Clean up fds */
Damien Miller035a5b42004-06-26 08:16:31 +10001699 startup_pipe = REEXEC_STARTUP_PIPE_FD;
Darren Tucker645ab752004-06-25 13:33:20 +10001700 close(config_s[1]);
Damien Miller035a5b42004-06-26 08:16:31 +10001701 close(REEXEC_CONFIG_PASS_FD);
1702 newsock = sock_out = sock_in = dup(STDIN_FILENO);
Darren Tucker645ab752004-06-25 13:33:20 +10001703 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1704 dup2(fd, STDIN_FILENO);
1705 dup2(fd, STDOUT_FILENO);
1706 if (fd > STDERR_FILENO)
1707 close(fd);
1708 }
Damien Miller035a5b42004-06-26 08:16:31 +10001709 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1710 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001711 }
1712
Damien Miller5428f641999-11-25 11:54:57 +11001713 /*
1714 * Disable the key regeneration alarm. We will not regenerate the
1715 * key since we are no longer in a position to give it to anyone. We
1716 * will not restart on SIGHUP since it no longer makes sense.
1717 */
Damien Miller95def091999-11-25 00:26:21 +11001718 alarm(0);
1719 signal(SIGALRM, SIG_DFL);
1720 signal(SIGHUP, SIG_DFL);
1721 signal(SIGTERM, SIG_DFL);
1722 signal(SIGQUIT, SIG_DFL);
1723 signal(SIGCHLD, SIG_DFL);
Damien Miller4e0f5e12000-08-29 11:05:50 +11001724 signal(SIGINT, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +11001725
Damien Miller5428f641999-11-25 11:54:57 +11001726 /*
1727 * Register our connection. This turns encryption off because we do
1728 * not have a key.
1729 */
Damien Miller95def091999-11-25 00:26:21 +11001730 packet_set_connection(sock_in, sock_out);
Damien Miller9786e6e2005-07-26 21:54:56 +10001731 packet_set_server();
Damien Miller95def091999-11-25 00:26:21 +11001732
Damien Miller4f1d6b22005-05-26 11:59:32 +10001733 /* Set SO_KEEPALIVE if requested. */
1734 if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1735 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1736 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1737
Damien Miller677257f2005-06-17 12:55:03 +10001738 if ((remote_port = get_remote_port()) < 0) {
1739 debug("get_remote_port failed");
1740 cleanup_exit(255);
1741 }
Damien Miller4d3fd542005-11-05 15:13:24 +11001742
1743 /*
1744 * We use get_canonical_hostname with usedns = 0 instead of
1745 * get_remote_ipaddr here so IP options will be checked.
1746 */
Damien Millereb13e552006-06-13 13:03:53 +10001747 (void) get_canonical_hostname(0);
1748 /*
1749 * The rest of the code depends on the fact that
1750 * get_remote_ipaddr() caches the remote ip, even if
1751 * the socket goes away.
1752 */
1753 remote_ip = get_remote_ipaddr();
Damien Miller95def091999-11-25 00:26:21 +11001754
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001755#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11001756 audit_connection_from(remote_ip, remote_port);
1757#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001758#ifdef LIBWRAP
Darren Tucker1f1e17b2008-02-28 23:20:48 +11001759 allow_severity = options.log_facility|LOG_INFO;
1760 deny_severity = options.log_facility|LOG_WARNING;
Damien Miller6a4a4b92001-11-12 11:07:11 +11001761 /* Check whether logins are denied from this host. */
Darren Tucker586b0b92004-06-25 13:34:31 +10001762 if (packet_connection_is_on_socket()) {
Damien Miller95def091999-11-25 00:26:21 +11001763 struct request_info req;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001764
Ben Lindstromce89dac2001-09-12 16:58:04 +00001765 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
Damien Miller95def091999-11-25 00:26:21 +11001766 fromhost(&req);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001767
Damien Miller95def091999-11-25 00:26:21 +11001768 if (!hosts_access(&req)) {
Damien Miller6a4a4b92001-11-12 11:07:11 +11001769 debug("Connection refused by tcp wrapper");
Ben Lindstrom7de696e2001-03-29 00:45:12 +00001770 refuse(&req);
Damien Miller6a4a4b92001-11-12 11:07:11 +11001771 /* NOTREACHED */
1772 fatal("libwrap refuse returns");
Damien Miller95def091999-11-25 00:26:21 +11001773 }
Damien Miller95def091999-11-25 00:26:21 +11001774 }
Damien Miller34132e52000-01-14 15:45:46 +11001775#endif /* LIBWRAP */
Damien Miller6a4a4b92001-11-12 11:07:11 +11001776
Damien Miller95def091999-11-25 00:26:21 +11001777 /* Log the connection. */
1778 verbose("Connection from %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001779
Damien Miller5428f641999-11-25 11:54:57 +11001780 /*
Damien Miller788f2122005-11-05 15:14:59 +11001781 * We don't want to listen forever unless the other side
Damien Miller5428f641999-11-25 11:54:57 +11001782 * successfully authenticates itself. So we set up an alarm which is
1783 * cleared after successful authentication. A limit of zero
Damien Miller788f2122005-11-05 15:14:59 +11001784 * indicates no limit. Note that we don't set the alarm in debugging
Damien Miller5428f641999-11-25 11:54:57 +11001785 * mode; it is just annoying to have the server exit just when you
1786 * are about to discover the bug.
1787 */
Ben Lindstrom5ade9ab2003-08-25 01:16:21 +00001788 signal(SIGALRM, grace_alarm_handler);
Damien Miller95def091999-11-25 00:26:21 +11001789 if (!debug_flag)
1790 alarm(options.login_grace_time);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001791
Damien Millerb38eff82000-04-01 11:09:21 +10001792 sshd_exchange_identification(sock_in, sock_out);
Darren Tuckerec960f22003-08-13 20:37:05 +10001793
Darren Tucker58911162008-01-01 20:33:09 +11001794 /* In inetd mode, generate ephemeral key only for proto 1 connections */
1795 if (!compat20 && inetd_flag && sensitive_data.server_key == NULL)
1796 generate_ephemeral_server_key();
1797
Damien Miller95def091999-11-25 00:26:21 +11001798 packet_set_nonblocking();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001799
Darren Tucker3e33cec2003-10-02 16:12:36 +10001800 /* allocate authentication context */
Damien Miller07d86be2006-03-26 14:19:21 +11001801 authctxt = xcalloc(1, sizeof(*authctxt));
Darren Tucker3e33cec2003-10-02 16:12:36 +10001802
Darren Tuckerf3bb4342005-03-31 21:39:25 +10001803 authctxt->loginmsg = &loginmsg;
1804
Darren Tucker3e33cec2003-10-02 16:12:36 +10001805 /* XXX global for cleanup, access from other modules */
1806 the_authctxt = authctxt;
1807
Darren Tucker5c14c732005-01-24 21:55:49 +11001808 /* prepare buffer to collect messages to display to user after login */
1809 buffer_init(&loginmsg);
1810
Ben Lindstrom943481c2002-03-22 03:43:46 +00001811 if (use_privsep)
Darren Tucker3e33cec2003-10-02 16:12:36 +10001812 if (privsep_preauth(authctxt) == 1)
Ben Lindstrom943481c2002-03-22 03:43:46 +00001813 goto authenticated;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001814
Damien Miller396691a2000-01-20 22:44:08 +11001815 /* perform the key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001816 /* authenticate user and start session */
Damien Millerefb4afe2000-04-12 18:45:05 +10001817 if (compat20) {
1818 do_ssh2_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001819 do_authentication2(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001820 } else {
1821 do_ssh1_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001822 do_authentication(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001823 }
Ben Lindstrom943481c2002-03-22 03:43:46 +00001824 /*
1825 * If we use privilege separation, the unprivileged child transfers
1826 * the current keystate and exits
1827 */
1828 if (use_privsep) {
Ben Lindstrom7339b2a2002-05-15 16:25:01 +00001829 mm_send_keystate(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001830 exit(0);
Ben Lindstrom943481c2002-03-22 03:43:46 +00001831 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001832
1833 authenticated:
Damien Miller7bff1a92005-12-24 14:59:12 +11001834 /*
1835 * Cancel the alarm we set to limit the time taken for
1836 * authentication.
1837 */
1838 alarm(0);
1839 signal(SIGALRM, SIG_DFL);
Damien Miller3f8123c2006-08-19 00:32:46 +10001840 authctxt->authenticated = 1;
Damien Miller7bff1a92005-12-24 14:59:12 +11001841 if (startup_pipe != -1) {
1842 close(startup_pipe);
1843 startup_pipe = -1;
1844 }
1845
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001846#ifdef SSH_AUDIT_EVENTS
1847 audit_event(SSH_AUTH_SUCCESS);
Darren Tucker269a1ea2005-02-03 00:20:53 +11001848#endif
1849
Ben Lindstrom6328ab32002-03-22 02:54:23 +00001850 /*
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001851 * In privilege separation, we fork another child and prepare
1852 * file descriptor passing.
1853 */
1854 if (use_privsep) {
Ben Lindstrom943481c2002-03-22 03:43:46 +00001855 privsep_postauth(authctxt);
1856 /* the monitor process [priv] will not return */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001857 if (!compat20)
1858 destroy_sensitive_data();
1859 }
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001860
Darren Tucker3e33cec2003-10-02 16:12:36 +10001861 /* Start session. */
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001862 do_authenticated(authctxt);
1863
Damien Miller3a5b0232002-03-13 13:19:42 +11001864 /* The connection has been terminated. */
1865 verbose("Closing connection to %.100s", remote_ip);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001866
Damien Millerbeb4ba51999-12-28 15:09:35 +11001867#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +10001868 if (options.use_pam)
1869 finish_pam();
Damien Millerbeb4ba51999-12-28 15:09:35 +11001870#endif /* USE_PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001871
Darren Tucker2b59a6d2005-03-06 22:38:51 +11001872#ifdef SSH_AUDIT_EVENTS
1873 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE));
1874#endif
1875
Damien Miller95def091999-11-25 00:26:21 +11001876 packet_close();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001877
1878 if (use_privsep)
1879 mm_terminate();
1880
Damien Miller95def091999-11-25 00:26:21 +11001881 exit(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001882}
1883
Damien Miller95def091999-11-25 00:26:21 +11001884/*
Ben Lindstromabcb1452002-03-22 01:10:21 +00001885 * Decrypt session_key_int using our private server key and private host key
1886 * (key with larger modulus first).
1887 */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001888int
Ben Lindstromabcb1452002-03-22 01:10:21 +00001889ssh1_session_key(BIGNUM *session_key_int)
1890{
1891 int rsafail = 0;
1892
Damien Millerf0b15df2006-03-26 13:59:20 +11001893 if (BN_cmp(sensitive_data.server_key->rsa->n,
1894 sensitive_data.ssh1_host_key->rsa->n) > 0) {
Ben Lindstromabcb1452002-03-22 01:10:21 +00001895 /* Server key has bigger modulus. */
1896 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
Damien Millerf0b15df2006-03-26 13:59:20 +11001897 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1898 SSH_KEY_BITS_RESERVED) {
1899 fatal("do_connection: %s: "
1900 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
Ben Lindstromabcb1452002-03-22 01:10:21 +00001901 get_remote_ipaddr(),
1902 BN_num_bits(sensitive_data.server_key->rsa->n),
1903 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1904 SSH_KEY_BITS_RESERVED);
1905 }
1906 if (rsa_private_decrypt(session_key_int, session_key_int,
1907 sensitive_data.server_key->rsa) <= 0)
1908 rsafail++;
1909 if (rsa_private_decrypt(session_key_int, session_key_int,
1910 sensitive_data.ssh1_host_key->rsa) <= 0)
1911 rsafail++;
1912 } else {
1913 /* Host key has bigger modulus (or they are equal). */
1914 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
Damien Millerf0b15df2006-03-26 13:59:20 +11001915 BN_num_bits(sensitive_data.server_key->rsa->n) +
1916 SSH_KEY_BITS_RESERVED) {
1917 fatal("do_connection: %s: "
1918 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
Ben Lindstromabcb1452002-03-22 01:10:21 +00001919 get_remote_ipaddr(),
1920 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1921 BN_num_bits(sensitive_data.server_key->rsa->n),
1922 SSH_KEY_BITS_RESERVED);
1923 }
1924 if (rsa_private_decrypt(session_key_int, session_key_int,
1925 sensitive_data.ssh1_host_key->rsa) < 0)
1926 rsafail++;
1927 if (rsa_private_decrypt(session_key_int, session_key_int,
1928 sensitive_data.server_key->rsa) < 0)
1929 rsafail++;
1930 }
1931 return (rsafail);
1932}
1933/*
Damien Miller396691a2000-01-20 22:44:08 +11001934 * SSH1 key exchange
Damien Miller95def091999-11-25 00:26:21 +11001935 */
Ben Lindstrombba81212001-06-25 05:01:22 +00001936static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001937do_ssh1_kex(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001938{
Damien Miller95def091999-11-25 00:26:21 +11001939 int i, len;
Damien Miller7650bc62001-01-30 09:27:26 +11001940 int rsafail = 0;
Damien Miller95def091999-11-25 00:26:21 +11001941 BIGNUM *session_key_int;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001942 u_char session_key[SSH_SESSION_KEY_LENGTH];
1943 u_char cookie[8];
1944 u_int cipher_type, auth_mask, protocol_flags;
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001945 u_int32_t rnd = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001946
Damien Miller5428f641999-11-25 11:54:57 +11001947 /*
1948 * Generate check bytes that the client must send back in the user
1949 * packet in order for it to be accepted; this is used to defy ip
1950 * spoofing attacks. Note that this only works against somebody
1951 * doing IP spoofing from a remote machine; any machine on the local
1952 * network can still see outgoing packets and catch the random
1953 * cookie. This only affects rhosts authentication, and this is one
1954 * of the reasons why it is inherently insecure.
1955 */
Damien Miller95def091999-11-25 00:26:21 +11001956 for (i = 0; i < 8; i++) {
1957 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001958 rnd = arc4random();
1959 cookie[i] = rnd & 0xff;
1960 rnd >>= 8;
Damien Miller95def091999-11-25 00:26:21 +11001961 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001962
Damien Miller5428f641999-11-25 11:54:57 +11001963 /*
1964 * Send our public key. We include in the packet 64 bits of random
1965 * data that must be matched in the reply in order to prevent IP
1966 * spoofing.
1967 */
Damien Miller95def091999-11-25 00:26:21 +11001968 packet_start(SSH_SMSG_PUBLIC_KEY);
1969 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001970 packet_put_char(cookie[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001971
Damien Miller95def091999-11-25 00:26:21 +11001972 /* Store our public server RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001973 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1974 packet_put_bignum(sensitive_data.server_key->rsa->e);
1975 packet_put_bignum(sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001976
Damien Miller95def091999-11-25 00:26:21 +11001977 /* Store our public host RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001978 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1979 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1980 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001981
Damien Miller95def091999-11-25 00:26:21 +11001982 /* Put protocol flags. */
1983 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001984
Damien Miller95def091999-11-25 00:26:21 +11001985 /* Declare which ciphers we support. */
Damien Miller874d77b2000-10-14 16:23:11 +11001986 packet_put_int(cipher_mask_ssh1(0));
Damien Miller95def091999-11-25 00:26:21 +11001987
1988 /* Declare supported authentication types. */
1989 auth_mask = 0;
Damien Miller95def091999-11-25 00:26:21 +11001990 if (options.rhosts_rsa_authentication)
1991 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1992 if (options.rsa_authentication)
1993 auth_mask |= 1 << SSH_AUTH_RSA;
Ben Lindstrom551ea372001-06-05 18:56:16 +00001994 if (options.challenge_response_authentication == 1)
Damien Miller95def091999-11-25 00:26:21 +11001995 auth_mask |= 1 << SSH_AUTH_TIS;
Damien Miller95def091999-11-25 00:26:21 +11001996 if (options.password_authentication)
1997 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1998 packet_put_int(auth_mask);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001999
Damien Miller95def091999-11-25 00:26:21 +11002000 /* Send the packet and wait for it to be sent. */
2001 packet_send();
2002 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002003
Damien Miller0bc1bd82000-11-13 22:57:25 +11002004 debug("Sent %d bit server key and %d bit host key.",
2005 BN_num_bits(sensitive_data.server_key->rsa->n),
2006 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002007
Damien Miller95def091999-11-25 00:26:21 +11002008 /* Read clients reply (cipher type and session key). */
Damien Millerdff50992002-01-22 23:16:32 +11002009 packet_read_expect(SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002010
Damien Miller50945fa1999-12-09 10:31:37 +11002011 /* Get cipher type and check whether we accept this. */
Damien Miller95def091999-11-25 00:26:21 +11002012 cipher_type = packet_get_char();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002013
Damien Miller874d77b2000-10-14 16:23:11 +11002014 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
Damien Miller50945fa1999-12-09 10:31:37 +11002015 packet_disconnect("Warning: client selects unsupported cipher.");
2016
Damien Miller95def091999-11-25 00:26:21 +11002017 /* Get check bytes from the packet. These must match those we
2018 sent earlier with the public key packet. */
2019 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11002020 if (cookie[i] != packet_get_char())
Damien Miller95def091999-11-25 00:26:21 +11002021 packet_disconnect("IP Spoofing check bytes do not match.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002022
Damien Miller95def091999-11-25 00:26:21 +11002023 debug("Encryption type: %.200s", cipher_name(cipher_type));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002024
Damien Miller95def091999-11-25 00:26:21 +11002025 /* Get the encrypted integer. */
Damien Millerda755162002-01-22 23:09:22 +11002026 if ((session_key_int = BN_new()) == NULL)
2027 fatal("do_ssh1_kex: BN_new failed");
Damien Millerd432ccf2002-01-22 23:14:44 +11002028 packet_get_bignum(session_key_int);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002029
Damien Miller95def091999-11-25 00:26:21 +11002030 protocol_flags = packet_get_int();
2031 packet_set_protocol_flags(protocol_flags);
Damien Miller48b03fc2002-01-22 23:11:40 +11002032 packet_check_eom();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002033
Ben Lindstromabcb1452002-03-22 01:10:21 +00002034 /* Decrypt session_key_int using host/server keys */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002035 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
2036
Damien Miller5428f641999-11-25 11:54:57 +11002037 /*
2038 * Extract session key from the decrypted integer. The key is in the
2039 * least significant 256 bits of the integer; the first byte of the
2040 * key is in the highest bits.
2041 */
Damien Miller7650bc62001-01-30 09:27:26 +11002042 if (!rsafail) {
Darren Tucker0bc85572006-11-07 23:14:41 +11002043 (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8);
Damien Miller7650bc62001-01-30 09:27:26 +11002044 len = BN_num_bytes(session_key_int);
Damien Millereccb9de2005-06-17 12:59:34 +10002045 if (len < 0 || (u_int)len > sizeof(session_key)) {
Darren Tucker0bc85572006-11-07 23:14:41 +11002046 error("do_ssh1_kex: bad session key len from %s: "
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00002047 "session_key_int %d > sizeof(session_key) %lu",
2048 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
Damien Miller7650bc62001-01-30 09:27:26 +11002049 rsafail++;
2050 } else {
2051 memset(session_key, 0, sizeof(session_key));
2052 BN_bn2bin(session_key_int,
2053 session_key + sizeof(session_key) - len);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002054
Darren Tuckere14e0052004-05-13 16:30:44 +10002055 derive_ssh1_session_id(
Darren Tuckerfc959702004-07-17 16:12:08 +10002056 sensitive_data.ssh1_host_key->rsa->n,
Darren Tuckere14e0052004-05-13 16:30:44 +10002057 sensitive_data.server_key->rsa->n,
2058 cookie, session_id);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002059 /*
2060 * Xor the first 16 bytes of the session key with the
2061 * session id.
2062 */
2063 for (i = 0; i < 16; i++)
2064 session_key[i] ^= session_id[i];
Damien Miller7650bc62001-01-30 09:27:26 +11002065 }
2066 }
2067 if (rsafail) {
Ben Lindstromeb648a72001-03-05 06:00:29 +00002068 int bytes = BN_num_bytes(session_key_int);
Ben Lindstrom13c5d3b2002-02-26 18:00:48 +00002069 u_char *buf = xmalloc(bytes);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002070 MD5_CTX md;
2071
Damien Miller996acd22003-04-09 20:59:48 +10002072 logit("do_connection: generating a fake encryption key");
Ben Lindstromeb648a72001-03-05 06:00:29 +00002073 BN_bn2bin(session_key_int, buf);
2074 MD5_Init(&md);
2075 MD5_Update(&md, buf, bytes);
2076 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
2077 MD5_Final(session_key, &md);
2078 MD5_Init(&md);
2079 MD5_Update(&md, session_key, 16);
2080 MD5_Update(&md, buf, bytes);
2081 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
2082 MD5_Final(session_key + 16, &md);
2083 memset(buf, 0, bytes);
2084 xfree(buf);
Ben Lindstrom941ac822001-03-05 06:25:23 +00002085 for (i = 0; i < 16; i++)
2086 session_id[i] = session_key[i] ^ session_key[i + 16];
Damien Miller7650bc62001-01-30 09:27:26 +11002087 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002088 /* Destroy the private and public keys. No longer. */
Damien Miller3a5b0232002-03-13 13:19:42 +11002089 destroy_sensitive_data();
Ben Lindstromeb648a72001-03-05 06:00:29 +00002090
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002091 if (use_privsep)
2092 mm_ssh1_session_id(session_id);
2093
Damien Miller396691a2000-01-20 22:44:08 +11002094 /* Destroy the decrypted integer. It is no longer needed. */
2095 BN_clear_free(session_key_int);
2096
Damien Miller95def091999-11-25 00:26:21 +11002097 /* Set the session key. From this on all communications will be encrypted. */
2098 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002099
Damien Miller95def091999-11-25 00:26:21 +11002100 /* Destroy our copy of the session key. It is no longer needed. */
2101 memset(session_key, 0, sizeof(session_key));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002102
Damien Miller95def091999-11-25 00:26:21 +11002103 debug("Received session key; encryption turned on.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002104
Ben Lindstromf666fec2002-06-06 19:51:58 +00002105 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
Damien Miller95def091999-11-25 00:26:21 +11002106 packet_start(SSH_SMSG_SUCCESS);
2107 packet_send();
2108 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002109}
Damien Millerefb4afe2000-04-12 18:45:05 +10002110
2111/*
2112 * SSH2 key exchange: diffie-hellman-group1-sha1
2113 */
Ben Lindstrombba81212001-06-25 05:01:22 +00002114static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00002115do_ssh2_kex(void)
Damien Millerefb4afe2000-04-12 18:45:05 +10002116{
Damien Millerefb4afe2000-04-12 18:45:05 +10002117 Kex *kex;
Damien Millerefb4afe2000-04-12 18:45:05 +10002118
Damien Miller78928792000-04-12 20:17:38 +10002119 if (options.ciphers != NULL) {
Damien Miller4af51302000-04-16 11:18:38 +10002120 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
Damien Miller78928792000-04-12 20:17:38 +10002121 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
2122 }
Damien Millera0ff4662001-03-30 10:49:35 +10002123 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
2124 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
2125 myproposal[PROPOSAL_ENC_ALGS_STOC] =
2126 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
2127
Ben Lindstrom06b33aa2001-02-15 03:01:59 +00002128 if (options.macs != NULL) {
2129 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2130 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2131 }
Damien Miller9786e6e2005-07-26 21:54:56 +10002132 if (options.compression == COMP_NONE) {
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002133 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2134 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
Damien Miller9786e6e2005-07-26 21:54:56 +10002135 } else if (options.compression == COMP_DELAYED) {
2136 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2137 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002138 }
Damien Millerf0b15df2006-03-26 13:59:20 +11002139
Damien Miller0bc1bd82000-11-13 22:57:25 +11002140 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
2141
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002142 /* start key exchange */
Ben Lindstrom238abf62001-04-04 17:52:53 +00002143 kex = kex_setup(myproposal);
Damien Miller8e7fb332003-02-24 12:03:03 +11002144 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
Damien Millerf675fc42004-06-15 10:30:09 +10002145 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
Damien Miller8e7fb332003-02-24 12:03:03 +11002146 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
Damien Millera63128d2006-03-15 12:08:28 +11002147 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002148 kex->server = 1;
2149 kex->client_version_string=client_version_string;
2150 kex->server_version_string=server_version_string;
2151 kex->load_host_key=&get_hostkey_by_type;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002152 kex->host_key_index=&get_hostkey_index;
Damien Millerefb4afe2000-04-12 18:45:05 +10002153
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002154 xxx_kex = kex;
2155
Ben Lindstrombe2cc432001-04-04 23:46:07 +00002156 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
Damien Miller874d77b2000-10-14 16:23:11 +11002157
Ben Lindstrom2d90e002001-04-04 02:00:54 +00002158 session_id2 = kex->session_id;
2159 session_id2_len = kex->session_id_len;
2160
Damien Miller874d77b2000-10-14 16:23:11 +11002161#ifdef DEBUG_KEXDH
2162 /* send 1st encrypted/maced/compressed message */
2163 packet_start(SSH2_MSG_IGNORE);
2164 packet_put_cstring("markus");
2165 packet_send();
2166 packet_write_wait();
2167#endif
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002168 debug("KEX done");
Damien Millerefb4afe2000-04-12 18:45:05 +10002169}
Darren Tucker3e33cec2003-10-02 16:12:36 +10002170
2171/* server specific fatal cleanup */
2172void
2173cleanup_exit(int i)
2174{
2175 if (the_authctxt)
2176 do_cleanup(the_authctxt);
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002177#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11002178 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
2179 if (!use_privsep || mm_is_monitor())
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002180 audit_event(SSH_CONNECTION_ABANDON);
Darren Tucker269a1ea2005-02-03 00:20:53 +11002181#endif
Darren Tucker3e33cec2003-10-02 16:12:36 +10002182 _exit(i);
2183}