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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
Damien Millere4340be2000-09-16 13:29:08 +11005 * This program is the ssh daemon. It listens for connections from clients,
6 * and performs authentication, executes use commands or shell, and forwards
Damien Miller95def091999-11-25 00:26:21 +11007 * information to/from the application to the user client over an encrypted
Damien Millere4340be2000-09-16 13:29:08 +11008 * connection. This can also handle forwarding of X11, TCP/IP, and
9 * authentication agent connections.
Damien Millerefb4afe2000-04-12 18:45:05 +100010 *
Damien Millere4340be2000-09-16 13:29:08 +110011 * As far as I am concerned, the code I have written for this software
12 * can be used freely for any purpose. Any derived versions of this
13 * software must be clearly marked as such, and if the derived work is
14 * incompatible with the protocol description in the RFC file, it must be
15 * called by a name other than "ssh" or "Secure Shell".
16 *
17 * SSH2 implementation:
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000018 * Privilege Separation:
Damien Millere4340be2000-09-16 13:29:08 +110019 *
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000020 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
21 * Copyright (c) 2002 Niels Provos. All rights reserved.
Damien Millere4340be2000-09-16 13:29:08 +110022 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the above copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 *
32 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
33 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
34 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
35 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
36 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
37 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
38 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
39 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
41 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Miller95def091999-11-25 00:26:21 +110042 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100043
44#include "includes.h"
Darren Tuckerec960f22003-08-13 20:37:05 +100045RCSID("$OpenBSD: sshd.c,v 1.275 2003/08/13 08:46:31 markus Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100046
Ben Lindstrom226cfa02001-01-22 05:34:40 +000047#include <openssl/dh.h>
48#include <openssl/bn.h>
Damien Miller6a47f302002-02-13 13:55:06 +110049#include <openssl/md5.h>
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000050#include <openssl/rand.h>
Kevin Steves0ea1d9d2002-04-25 18:17:04 +000051#ifdef HAVE_SECUREWARE
52#include <sys/security.h>
53#include <prot.h>
54#endif
Ben Lindstrom226cfa02001-01-22 05:34:40 +000055
56#include "ssh.h"
57#include "ssh1.h"
58#include "ssh2.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100059#include "xmalloc.h"
60#include "rsa.h"
Ben Lindstromd95c09c2001-02-18 19:13:33 +000061#include "sshpty.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100062#include "packet.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100063#include "mpaux.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000064#include "log.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100065#include "servconf.h"
66#include "uidswap.h"
67#include "compat.h"
Damien Millerb38eff82000-04-01 11:09:21 +100068#include "buffer.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000069#include "cipher.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100070#include "kex.h"
Damien Millerb38eff82000-04-01 11:09:21 +100071#include "key.h"
Damien Miller874d77b2000-10-14 16:23:11 +110072#include "dh.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100073#include "myproposal.h"
Damien Millereba71ba2000-04-29 23:57:08 +100074#include "authfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000075#include "pathnames.h"
76#include "atomicio.h"
77#include "canohost.h"
78#include "auth.h"
79#include "misc.h"
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +000080#include "dispatch.h"
Ben Lindstrom1bae4042001-10-03 17:46:39 +000081#include "channels.h"
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +000082#include "session.h"
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000083#include "monitor_mm.h"
84#include "monitor.h"
85#include "monitor_wrap.h"
86#include "monitor_fdpass.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100087
88#ifdef LIBWRAP
89#include <tcpd.h>
90#include <syslog.h>
91int allow_severity = LOG_INFO;
92int deny_severity = LOG_WARNING;
93#endif /* LIBWRAP */
94
95#ifndef O_NOCTTY
96#define O_NOCTTY 0
97#endif
98
Ben Lindstrom49a79c02000-11-17 03:47:20 +000099#ifdef HAVE___PROGNAME
100extern char *__progname;
101#else
102char *__progname;
103#endif
104
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000105/* Server configuration options. */
106ServerOptions options;
107
108/* Name of the server configuration file. */
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000109char *config_file_name = _PATH_SERVER_CONFIG_FILE;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000110
Damien Miller4af51302000-04-16 11:18:38 +1000111/*
Damien Miller34132e52000-01-14 15:45:46 +1100112 * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
113 * Default value is AF_UNSPEC means both IPv4 and IPv6.
114 */
115int IPv4or6 = AF_UNSPEC;
116
Damien Miller95def091999-11-25 00:26:21 +1100117/*
118 * Debug mode flag. This can be set on the command line. If debug
119 * mode is enabled, extra debugging output will be sent to the system
120 * log, the daemon will not go to background, and will exit after processing
121 * the first connection.
122 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000123int debug_flag = 0;
124
Ben Lindstrom794325a2001-08-06 21:09:07 +0000125/* Flag indicating that the daemon should only test the configuration and keys. */
126int test_flag = 0;
127
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000128/* Flag indicating that the daemon is being started from inetd. */
129int inetd_flag = 0;
130
Ben Lindstromc72745a2000-12-02 19:03:54 +0000131/* Flag indicating that sshd should not detach and become a daemon. */
132int no_daemon_flag = 0;
133
Damien Miller5ce662a1999-11-11 17:57:39 +1100134/* debug goes to stderr unless inetd_flag is set */
135int log_stderr = 0;
136
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000137/* Saved arguments to main(). */
138char **saved_argv;
Damien Millerb8c656e2000-06-28 15:22:41 +1000139int saved_argc;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000140
Damien Miller5428f641999-11-25 11:54:57 +1100141/*
Damien Miller34132e52000-01-14 15:45:46 +1100142 * The sockets that the server is listening; this is used in the SIGHUP
143 * signal handler.
Damien Miller5428f641999-11-25 11:54:57 +1100144 */
Damien Miller34132e52000-01-14 15:45:46 +1100145#define MAX_LISTEN_SOCKS 16
146int listen_socks[MAX_LISTEN_SOCKS];
147int num_listen_socks = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000148
Damien Miller5428f641999-11-25 11:54:57 +1100149/*
150 * the client's version string, passed by sshd2 in compat mode. if != NULL,
151 * sshd will skip the version-number exchange
152 */
Damien Miller95def091999-11-25 00:26:21 +1100153char *client_version_string = NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000154char *server_version_string = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000155
Ben Lindstrom8ac91062001-04-04 17:57:54 +0000156/* for rekeying XXX fixme */
157Kex *xxx_kex;
158
Damien Miller5428f641999-11-25 11:54:57 +1100159/*
160 * Any really sensitive data in the application is contained in this
161 * structure. The idea is that this structure could be locked into memory so
162 * that the pages do not get written into swap. However, there are some
163 * problems. The private key contains BIGNUMs, and we do not (in principle)
164 * have access to the internals of them, and locking just the structure is
165 * not very useful. Currently, memory locking is not implemented.
166 */
Damien Miller95def091999-11-25 00:26:21 +1100167struct {
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000168 Key *server_key; /* ephemeral server key */
Damien Miller0bc1bd82000-11-13 22:57:25 +1100169 Key *ssh1_host_key; /* ssh1 host key */
170 Key **host_keys; /* all private host keys */
171 int have_ssh1_key;
172 int have_ssh2_key;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000173 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000174} sensitive_data;
175
Damien Miller5428f641999-11-25 11:54:57 +1100176/*
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000177 * Flag indicating whether the RSA server key needs to be regenerated.
178 * Is set in the SIGALRM handler and cleared when the key is regenerated.
Damien Miller5428f641999-11-25 11:54:57 +1100179 */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000180static volatile sig_atomic_t key_do_regen = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000181
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000182/* This is set to true when a signal is received. */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000183static volatile sig_atomic_t received_sighup = 0;
184static volatile sig_atomic_t received_sigterm = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000185
Damien Millerb38eff82000-04-01 11:09:21 +1000186/* session identifier, used by RSA-auth */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000187u_char session_id[16];
Damien Millerb38eff82000-04-01 11:09:21 +1000188
Damien Millereba71ba2000-04-29 23:57:08 +1000189/* same for ssh2 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000190u_char *session_id2 = NULL;
Darren Tucker502d3842003-06-28 12:38:01 +1000191u_int session_id2_len = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000192
Damien Miller942da032000-08-18 13:59:06 +1000193/* record remote hostname or ip */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000194u_int utmp_len = MAXHOSTNAMELEN;
Damien Miller942da032000-08-18 13:59:06 +1000195
Ben Lindstromd84df982001-12-06 16:35:40 +0000196/* options.max_startup sized array of fd ints */
197int *startup_pipes = NULL;
198int startup_pipe; /* in child */
199
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000200/* variables used for privilege separation */
Damien Miller8e7fb332003-02-24 12:03:03 +1100201int use_privsep;
202struct monitor *pmonitor;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000203
Darren Tuckerb9aa0a02003-07-08 22:59:59 +1000204/* message to be displayed after login */
205Buffer loginmsg;
206
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000207/* Prototypes for various functions defined later in this file. */
Ben Lindstrombba81212001-06-25 05:01:22 +0000208void destroy_sensitive_data(void);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000209void demote_sensitive_data(void);
Damien Miller98c7ad62000-03-09 21:27:49 +1100210
Ben Lindstrombba81212001-06-25 05:01:22 +0000211static void do_ssh1_kex(void);
212static void do_ssh2_kex(void);
Damien Miller874d77b2000-10-14 16:23:11 +1100213
Damien Miller98c7ad62000-03-09 21:27:49 +1100214/*
Damien Miller34132e52000-01-14 15:45:46 +1100215 * Close all listening sockets
216 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000217static void
Damien Miller34132e52000-01-14 15:45:46 +1100218close_listen_socks(void)
219{
220 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000221
Damien Miller34132e52000-01-14 15:45:46 +1100222 for (i = 0; i < num_listen_socks; i++)
223 close(listen_socks[i]);
224 num_listen_socks = -1;
225}
226
Ben Lindstromd84df982001-12-06 16:35:40 +0000227static void
228close_startup_pipes(void)
229{
230 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000231
Ben Lindstromd84df982001-12-06 16:35:40 +0000232 if (startup_pipes)
233 for (i = 0; i < options.max_startups; i++)
234 if (startup_pipes[i] != -1)
235 close(startup_pipes[i]);
236}
237
Damien Miller34132e52000-01-14 15:45:46 +1100238/*
Damien Miller95def091999-11-25 00:26:21 +1100239 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
240 * the effect is to reread the configuration file (and to regenerate
241 * the server key).
242 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000243static void
Damien Miller95def091999-11-25 00:26:21 +1100244sighup_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000245{
Ben Lindstrom07958482001-12-06 16:19:01 +0000246 int save_errno = errno;
247
Damien Miller95def091999-11-25 00:26:21 +1100248 received_sighup = 1;
249 signal(SIGHUP, sighup_handler);
Ben Lindstrom07958482001-12-06 16:19:01 +0000250 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000251}
252
Damien Miller95def091999-11-25 00:26:21 +1100253/*
254 * Called from the main program after receiving SIGHUP.
255 * Restarts the server.
256 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000257static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000258sighup_restart(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000259{
Damien Miller996acd22003-04-09 20:59:48 +1000260 logit("Received SIGHUP; restarting.");
Damien Miller34132e52000-01-14 15:45:46 +1100261 close_listen_socks();
Ben Lindstromd84df982001-12-06 16:35:40 +0000262 close_startup_pipes();
Damien Miller95def091999-11-25 00:26:21 +1100263 execv(saved_argv[0], saved_argv);
Damien Miller996acd22003-04-09 20:59:48 +1000264 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
Ben Lindstrom822b6342002-06-23 21:38:49 +0000265 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100266 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000267}
268
Damien Miller95def091999-11-25 00:26:21 +1100269/*
270 * Generic signal handler for terminating signals in the master daemon.
Damien Miller95def091999-11-25 00:26:21 +1100271 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000272static void
Damien Miller95def091999-11-25 00:26:21 +1100273sigterm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000274{
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000275 received_sigterm = sig;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000276}
277
Damien Miller95def091999-11-25 00:26:21 +1100278/*
279 * SIGCHLD handler. This is called whenever a child dies. This will then
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000280 * reap any zombies left by exited children.
Damien Miller95def091999-11-25 00:26:21 +1100281 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000282static void
Damien Miller95def091999-11-25 00:26:21 +1100283main_sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000284{
Damien Miller95def091999-11-25 00:26:21 +1100285 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000286 pid_t pid;
Damien Miller95def091999-11-25 00:26:21 +1100287 int status;
Damien Miller431f66b1999-11-21 18:31:57 +1100288
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000289 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
290 (pid < 0 && errno == EINTR))
Damien Miller95def091999-11-25 00:26:21 +1100291 ;
Damien Miller431f66b1999-11-21 18:31:57 +1100292
Damien Miller95def091999-11-25 00:26:21 +1100293 signal(SIGCHLD, main_sigchld_handler);
294 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000295}
296
Damien Miller95def091999-11-25 00:26:21 +1100297/*
298 * Signal handler for the alarm after the login grace period has expired.
299 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000300static void
Damien Miller95def091999-11-25 00:26:21 +1100301grace_alarm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000302{
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000303 /* XXX no idea how fix this signal handler */
304
Damien Miller95def091999-11-25 00:26:21 +1100305 /* Log error and exit. */
Damien Millerd27a76d2002-09-27 13:22:31 +1000306 fatal("Timeout before authentication for %s", get_remote_ipaddr());
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000307}
308
Damien Miller95def091999-11-25 00:26:21 +1100309/*
Damien Miller95def091999-11-25 00:26:21 +1100310 * Signal handler for the key regeneration alarm. Note that this
311 * alarm only occurs in the daemon waiting for connections, and it does not
312 * do anything with the private key or random state before forking.
313 * Thus there should be no concurrency control/asynchronous execution
314 * problems.
315 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000316static void
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000317generate_ephemeral_server_key(void)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100318{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000319 u_int32_t rnd = 0;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000320 int i;
321
Ben Lindstroma3700052001-04-05 23:26:32 +0000322 verbose("Generating %s%d bit RSA key.",
Damien Millerff75ac42001-03-30 10:50:32 +1000323 sensitive_data.server_key ? "new " : "", options.server_key_bits);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100324 if (sensitive_data.server_key != NULL)
325 key_free(sensitive_data.server_key);
Ben Lindstroma3700052001-04-05 23:26:32 +0000326 sensitive_data.server_key = key_generate(KEY_RSA1,
Damien Millerff75ac42001-03-30 10:50:32 +1000327 options.server_key_bits);
328 verbose("RSA key generation complete.");
Ben Lindstromeb648a72001-03-05 06:00:29 +0000329
330 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
331 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000332 rnd = arc4random();
333 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
334 rnd >>= 8;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000335 }
336 arc4random_stir();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100337}
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000338
Ben Lindstrombba81212001-06-25 05:01:22 +0000339static void
Damien Miller95def091999-11-25 00:26:21 +1100340key_regeneration_alarm(int sig)
341{
342 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000343
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000344 signal(SIGALRM, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +1100345 errno = save_errno;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000346 key_do_regen = 1;
Damien Miller95def091999-11-25 00:26:21 +1100347}
348
Ben Lindstrombba81212001-06-25 05:01:22 +0000349static void
Damien Millerb38eff82000-04-01 11:09:21 +1000350sshd_exchange_identification(int sock_in, int sock_out)
351{
Damien Miller78928792000-04-12 20:17:38 +1000352 int i, mismatch;
Damien Millerb38eff82000-04-01 11:09:21 +1000353 int remote_major, remote_minor;
Damien Miller78928792000-04-12 20:17:38 +1000354 int major, minor;
Damien Millerb38eff82000-04-01 11:09:21 +1000355 char *s;
356 char buf[256]; /* Must not be larger than remote_version. */
357 char remote_version[256]; /* Must be at least as big as buf. */
358
Damien Miller78928792000-04-12 20:17:38 +1000359 if ((options.protocol & SSH_PROTO_1) &&
360 (options.protocol & SSH_PROTO_2)) {
361 major = PROTOCOL_MAJOR_1;
362 minor = 99;
363 } else if (options.protocol & SSH_PROTO_2) {
364 major = PROTOCOL_MAJOR_2;
365 minor = PROTOCOL_MINOR_2;
366 } else {
367 major = PROTOCOL_MAJOR_1;
368 minor = PROTOCOL_MINOR_1;
369 }
370 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
Damien Millerb38eff82000-04-01 11:09:21 +1000371 server_version_string = xstrdup(buf);
372
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000373 /* Send our protocol version identification. */
374 if (atomicio(vwrite, sock_out, server_version_string,
375 strlen(server_version_string))
376 != strlen(server_version_string)) {
377 logit("Could not write ident string to %s", get_remote_ipaddr());
378 fatal_cleanup();
379 }
380
381 /* Read other sides version identification. */
382 memset(buf, 0, sizeof(buf));
383 for (i = 0; i < sizeof(buf) - 1; i++) {
384 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
385 logit("Did not receive identification string from %s",
386 get_remote_ipaddr());
Damien Millerb38eff82000-04-01 11:09:21 +1000387 fatal_cleanup();
388 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000389 if (buf[i] == '\r') {
390 buf[i] = 0;
391 /* Kludge for F-Secure Macintosh < 1.0.2 */
392 if (i == 12 &&
393 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
Damien Millerb38eff82000-04-01 11:09:21 +1000394 break;
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000395 continue;
Damien Millerb38eff82000-04-01 11:09:21 +1000396 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000397 if (buf[i] == '\n') {
398 buf[i] = 0;
399 break;
400 }
Damien Millerb38eff82000-04-01 11:09:21 +1000401 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000402 buf[sizeof(buf) - 1] = 0;
403 client_version_string = xstrdup(buf);
Damien Millerb38eff82000-04-01 11:09:21 +1000404
405 /*
406 * Check that the versions match. In future this might accept
407 * several versions and set appropriate flags to handle them.
408 */
409 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
410 &remote_major, &remote_minor, remote_version) != 3) {
Damien Miller4af51302000-04-16 11:18:38 +1000411 s = "Protocol mismatch.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000412 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Millerb38eff82000-04-01 11:09:21 +1000413 close(sock_in);
414 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000415 logit("Bad protocol version identification '%.100s' from %s",
Damien Millerb38eff82000-04-01 11:09:21 +1000416 client_version_string, get_remote_ipaddr());
417 fatal_cleanup();
418 }
419 debug("Client protocol version %d.%d; client software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100420 remote_major, remote_minor, remote_version);
Damien Millerb38eff82000-04-01 11:09:21 +1000421
Damien Millerefb4afe2000-04-12 18:45:05 +1000422 compat_datafellows(remote_version);
423
Damien Millere9264972002-09-30 11:59:21 +1000424 if (datafellows & SSH_BUG_PROBE) {
Damien Miller996acd22003-04-09 20:59:48 +1000425 logit("probed from %s with %s. Don't panic.",
Damien Millere9264972002-09-30 11:59:21 +1000426 get_remote_ipaddr(), client_version_string);
427 fatal_cleanup();
428 }
429
Damien Miller27dbe6f2001-03-19 22:36:20 +1100430 if (datafellows & SSH_BUG_SCANNER) {
Damien Miller996acd22003-04-09 20:59:48 +1000431 logit("scanned from %s with %s. Don't panic.",
Damien Miller27dbe6f2001-03-19 22:36:20 +1100432 get_remote_ipaddr(), client_version_string);
433 fatal_cleanup();
434 }
435
Damien Miller78928792000-04-12 20:17:38 +1000436 mismatch = 0;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000437 switch (remote_major) {
Damien Millerb38eff82000-04-01 11:09:21 +1000438 case 1:
Damien Millereba71ba2000-04-29 23:57:08 +1000439 if (remote_minor == 99) {
440 if (options.protocol & SSH_PROTO_2)
441 enable_compat20();
442 else
443 mismatch = 1;
444 break;
445 }
Damien Miller78928792000-04-12 20:17:38 +1000446 if (!(options.protocol & SSH_PROTO_1)) {
447 mismatch = 1;
448 break;
449 }
Damien Millerb38eff82000-04-01 11:09:21 +1000450 if (remote_minor < 3) {
Damien Miller37023962000-07-11 17:31:38 +1000451 packet_disconnect("Your ssh version is too old and "
Damien Millerb38eff82000-04-01 11:09:21 +1000452 "is no longer supported. Please install a newer version.");
453 } else if (remote_minor == 3) {
454 /* note that this disables agent-forwarding */
455 enable_compat13();
456 }
Damien Miller78928792000-04-12 20:17:38 +1000457 break;
Damien Millerefb4afe2000-04-12 18:45:05 +1000458 case 2:
Damien Miller78928792000-04-12 20:17:38 +1000459 if (options.protocol & SSH_PROTO_2) {
Damien Millerefb4afe2000-04-12 18:45:05 +1000460 enable_compat20();
461 break;
462 }
463 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000464 default:
Damien Miller78928792000-04-12 20:17:38 +1000465 mismatch = 1;
Damien Millerb38eff82000-04-01 11:09:21 +1000466 break;
467 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000468 chop(server_version_string);
Damien Miller78928792000-04-12 20:17:38 +1000469 debug("Local version string %.200s", server_version_string);
470
471 if (mismatch) {
472 s = "Protocol major versions differ.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000473 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Miller78928792000-04-12 20:17:38 +1000474 close(sock_in);
475 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000476 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
Damien Miller78928792000-04-12 20:17:38 +1000477 get_remote_ipaddr(),
478 server_version_string, client_version_string);
479 fatal_cleanup();
480 }
Damien Millereba71ba2000-04-29 23:57:08 +1000481}
482
Damien Miller0bc1bd82000-11-13 22:57:25 +1100483/* Destroy the host and server keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +1000484void
485destroy_sensitive_data(void)
486{
Damien Miller0bc1bd82000-11-13 22:57:25 +1100487 int i;
488
489 if (sensitive_data.server_key) {
490 key_free(sensitive_data.server_key);
491 sensitive_data.server_key = NULL;
492 }
Damien Miller9f0f5c62001-12-21 14:45:46 +1100493 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100494 if (sensitive_data.host_keys[i]) {
495 key_free(sensitive_data.host_keys[i]);
496 sensitive_data.host_keys[i] = NULL;
497 }
498 }
499 sensitive_data.ssh1_host_key = NULL;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000500 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100501}
Damien Miller0bc1bd82000-11-13 22:57:25 +1100502
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000503/* Demote private to public keys for network child */
504void
505demote_sensitive_data(void)
506{
507 Key *tmp;
508 int i;
509
510 if (sensitive_data.server_key) {
511 tmp = key_demote(sensitive_data.server_key);
512 key_free(sensitive_data.server_key);
513 sensitive_data.server_key = tmp;
514 }
515
516 for (i = 0; i < options.num_host_key_files; i++) {
517 if (sensitive_data.host_keys[i]) {
518 tmp = key_demote(sensitive_data.host_keys[i]);
519 key_free(sensitive_data.host_keys[i]);
520 sensitive_data.host_keys[i] = tmp;
521 if (tmp->type == KEY_RSA1)
522 sensitive_data.ssh1_host_key = tmp;
523 }
524 }
525
526 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
527}
528
Ben Lindstrom08105192002-03-22 02:50:06 +0000529static void
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000530privsep_preauth_child(void)
531{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000532 u_int32_t rnd[256];
Ben Lindstrom810af962002-07-04 00:11:40 +0000533 gid_t gidset[1];
Ben Lindstromc7431342002-03-22 03:11:49 +0000534 struct passwd *pw;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000535 int i;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000536
537 /* Enable challenge-response authentication for privilege separation */
538 privsep_challenge_enable();
539
540 for (i = 0; i < 256; i++)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000541 rnd[i] = arc4random();
542 RAND_seed(rnd, sizeof(rnd));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000543
544 /* Demote the private keys to public keys. */
545 demote_sensitive_data();
546
Ben Lindstromc7431342002-03-22 03:11:49 +0000547 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
Damien Miller0150c652002-04-24 09:49:09 +1000548 fatal("Privilege separation user %s does not exist",
549 SSH_PRIVSEP_USER);
Ben Lindstromc7431342002-03-22 03:11:49 +0000550 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
551 endpwent();
552
Ben Lindstroma962c2f2002-07-04 00:14:17 +0000553 /* Change our root directory */
Ben Lindstrom7a7edf72002-03-22 02:42:37 +0000554 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
555 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
556 strerror(errno));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000557 if (chdir("/") == -1)
Ben Lindstrom1ee9ec32002-03-22 03:14:45 +0000558 fatal("chdir(\"/\"): %s", strerror(errno));
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000559
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000560 /* Drop our privileges */
Ben Lindstromc7431342002-03-22 03:11:49 +0000561 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
562 (u_int)pw->pw_gid);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000563#if 0
564 /* XXX not ready, to heavy after chroot */
Ben Lindstromc7431342002-03-22 03:11:49 +0000565 do_setusercontext(pw);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000566#else
567 gidset[0] = pw->pw_gid;
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000568 if (setgroups(1, gidset) < 0)
569 fatal("setgroups: %.100s", strerror(errno));
570 permanently_set_uid(pw);
571#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000572}
573
Ben Lindstroma962c2f2002-07-04 00:14:17 +0000574static Authctxt *
Ben Lindstrom943481c2002-03-22 03:43:46 +0000575privsep_preauth(void)
576{
577 Authctxt *authctxt = NULL;
578 int status;
579 pid_t pid;
580
581 /* Set up unprivileged child process to deal with network data */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000582 pmonitor = monitor_init();
Ben Lindstrom943481c2002-03-22 03:43:46 +0000583 /* Store a pointer to the kex for later rekeying */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000584 pmonitor->m_pkex = &xxx_kex;
Ben Lindstrom943481c2002-03-22 03:43:46 +0000585
586 pid = fork();
587 if (pid == -1) {
588 fatal("fork of unprivileged child failed");
589 } else if (pid != 0) {
Ben Lindstrom264ee302002-07-23 21:01:56 +0000590 fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
591
Ben Lindstromce0f6342002-06-11 16:42:49 +0000592 debug2("Network child is on pid %ld", (long)pid);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000593
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000594 close(pmonitor->m_recvfd);
595 authctxt = monitor_child_preauth(pmonitor);
596 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000597
598 /* Sync memory */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000599 monitor_sync(pmonitor);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000600
601 /* Wait for the child's exit status */
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000602 while (waitpid(pid, &status, 0) < 0)
603 if (errno != EINTR)
604 break;
Ben Lindstrom264ee302002-07-23 21:01:56 +0000605
606 /* Reinstall, since the child has finished */
607 fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
608
Ben Lindstrom943481c2002-03-22 03:43:46 +0000609 return (authctxt);
610 } else {
611 /* child */
612
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000613 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000614
615 /* Demote the child */
616 if (getuid() == 0 || geteuid() == 0)
617 privsep_preauth_child();
Ben Lindstromf90f58d2002-03-26 01:53:03 +0000618 setproctitle("%s", "[net]");
Ben Lindstrom943481c2002-03-22 03:43:46 +0000619 }
620 return (NULL);
621}
622
Ben Lindstrom08105192002-03-22 02:50:06 +0000623static void
Ben Lindstrom943481c2002-03-22 03:43:46 +0000624privsep_postauth(Authctxt *authctxt)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000625{
626 extern Authctxt *x_authctxt;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000627
628 /* XXX - Remote port forwarding */
629 x_authctxt = authctxt;
630
Tim Rice9dd30812002-07-07 13:43:36 -0700631#ifdef DISABLE_FD_PASSING
Tim Rice8eff3192002-06-25 15:35:15 -0700632 if (1) {
633#else
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000634 if (authctxt->pw->pw_uid == 0 || options.use_login) {
Tim Rice8eff3192002-06-25 15:35:15 -0700635#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000636 /* File descriptor passing is broken or root login */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000637 monitor_apply_keystate(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000638 use_privsep = 0;
639 return;
640 }
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000641
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000642 /* Authentication complete */
643 alarm(0);
644 if (startup_pipe != -1) {
645 close(startup_pipe);
646 startup_pipe = -1;
647 }
648
649 /* New socket pair */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000650 monitor_reinit(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000651
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000652 pmonitor->m_pid = fork();
653 if (pmonitor->m_pid == -1)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000654 fatal("fork of unprivileged child failed");
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000655 else if (pmonitor->m_pid != 0) {
Ben Lindstrom264ee302002-07-23 21:01:56 +0000656 fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
657
Ben Lindstromce0f6342002-06-11 16:42:49 +0000658 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000659 close(pmonitor->m_recvfd);
660 monitor_child_postauth(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000661
662 /* NEVERREACHED */
663 exit(0);
664 }
665
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000666 close(pmonitor->m_sendfd);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000667
668 /* Demote the private keys to public keys. */
669 demote_sensitive_data();
670
671 /* Drop privileges */
672 do_setusercontext(authctxt->pw);
673
674 /* It is safe now to apply the key state */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000675 monitor_apply_keystate(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000676}
677
Ben Lindstrombba81212001-06-25 05:01:22 +0000678static char *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100679list_hostkey_types(void)
680{
Damien Miller0e3b8722002-01-22 23:26:38 +1100681 Buffer b;
682 char *p;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100683 int i;
Damien Miller0e3b8722002-01-22 23:26:38 +1100684
685 buffer_init(&b);
Damien Miller9f0f5c62001-12-21 14:45:46 +1100686 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100687 Key *key = sensitive_data.host_keys[i];
688 if (key == NULL)
689 continue;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000690 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100691 case KEY_RSA:
692 case KEY_DSA:
Damien Miller0e3b8722002-01-22 23:26:38 +1100693 if (buffer_len(&b) > 0)
694 buffer_append(&b, ",", 1);
695 p = key_ssh_name(key);
696 buffer_append(&b, p, strlen(p));
Damien Miller0bc1bd82000-11-13 22:57:25 +1100697 break;
698 }
699 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100700 buffer_append(&b, "\0", 1);
701 p = xstrdup(buffer_ptr(&b));
702 buffer_free(&b);
703 debug("list_hostkey_types: %s", p);
704 return p;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100705}
706
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000707Key *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100708get_hostkey_by_type(int type)
709{
710 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000711
Damien Miller9f0f5c62001-12-21 14:45:46 +1100712 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100713 Key *key = sensitive_data.host_keys[i];
714 if (key != NULL && key->type == type)
715 return key;
716 }
717 return NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000718}
719
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000720Key *
721get_hostkey_by_index(int ind)
722{
723 if (ind < 0 || ind >= options.num_host_key_files)
724 return (NULL);
725 return (sensitive_data.host_keys[ind]);
726}
727
728int
729get_hostkey_index(Key *key)
730{
731 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000732
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000733 for (i = 0; i < options.num_host_key_files; i++) {
734 if (key == sensitive_data.host_keys[i])
735 return (i);
736 }
737 return (-1);
738}
739
Damien Miller942da032000-08-18 13:59:06 +1000740/*
741 * returns 1 if connection should be dropped, 0 otherwise.
742 * dropping starts at connection #max_startups_begin with a probability
743 * of (max_startups_rate/100). the probability increases linearly until
744 * all connections are dropped for startups > max_startups
745 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000746static int
Damien Miller942da032000-08-18 13:59:06 +1000747drop_connection(int startups)
748{
749 double p, r;
750
751 if (startups < options.max_startups_begin)
752 return 0;
753 if (startups >= options.max_startups)
754 return 1;
755 if (options.max_startups_rate == 100)
756 return 1;
757
758 p = 100 - options.max_startups_rate;
759 p *= startups - options.max_startups_begin;
760 p /= (double) (options.max_startups - options.max_startups_begin);
761 p += options.max_startups_rate;
762 p /= 100.0;
763 r = arc4random() / (double) UINT_MAX;
764
765 debug("drop_connection: p %g, r %g", p, r);
766 return (r < p) ? 1 : 0;
767}
768
Ben Lindstromade03f62001-12-06 18:22:17 +0000769static void
770usage(void)
771{
772 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
773 fprintf(stderr, "Usage: %s [options]\n", __progname);
774 fprintf(stderr, "Options:\n");
775 fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
776 fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
777 fprintf(stderr, " -i Started from inetd\n");
778 fprintf(stderr, " -D Do not fork into daemon mode\n");
779 fprintf(stderr, " -t Only test configuration file and keys\n");
780 fprintf(stderr, " -q Quiet (no logging)\n");
781 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
782 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
783 fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
784 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
785 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
786 _PATH_HOST_KEY_FILE);
787 fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
788 fprintf(stderr, " -4 Use IPv4 only\n");
789 fprintf(stderr, " -6 Use IPv6 only\n");
790 fprintf(stderr, " -o option Process the option as if it was read from a configuration file.\n");
791 exit(1);
792}
793
Damien Miller95def091999-11-25 00:26:21 +1100794/*
795 * Main program for the daemon.
796 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000797int
798main(int ac, char **av)
799{
Damien Miller95def091999-11-25 00:26:21 +1100800 extern char *optarg;
801 extern int optind;
Damien Miller37023962000-07-11 17:31:38 +1000802 int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
Damien Miller166fca82000-04-20 07:42:21 +1000803 pid_t pid;
Damien Miller34132e52000-01-14 15:45:46 +1100804 socklen_t fromlen;
Damien Miller34132e52000-01-14 15:45:46 +1100805 fd_set *fdset;
806 struct sockaddr_storage from;
Damien Miller95def091999-11-25 00:26:21 +1100807 const char *remote_ip;
808 int remote_port;
Damien Miller95def091999-11-25 00:26:21 +1100809 FILE *f;
Damien Miller34132e52000-01-14 15:45:46 +1100810 struct addrinfo *ai;
811 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
812 int listen_sock, maxfd;
Damien Miller37023962000-07-11 17:31:38 +1000813 int startup_p[2];
814 int startups = 0;
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +0000815 Authctxt *authctxt;
Ben Lindstromd0fca422001-03-26 13:44:06 +0000816 Key *key;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000817 int ret, key_used = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000818
Kevin Steves0ea1d9d2002-04-25 18:17:04 +0000819#ifdef HAVE_SECUREWARE
820 (void)set_auth_parameters(ac, av);
821#endif
Damien Miller59d3d5b2003-08-22 09:34:41 +1000822 __progname = ssh_get_progname(av[0]);
Damien Millerf9b625c2000-07-09 22:42:32 +1000823 init_rng();
824
Damien Millera8ed44b2003-01-10 09:53:12 +1100825 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
Damien Millerb8c656e2000-06-28 15:22:41 +1000826 saved_argc = ac;
Damien Miller04cb5362003-05-15 21:29:10 +1000827 saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1));
Damien Millera8ed44b2003-01-10 09:53:12 +1100828 for (i = 0; i < ac; i++)
829 saved_argv[i] = xstrdup(av[i]);
Damien Miller04cb5362003-05-15 21:29:10 +1000830 saved_argv[i] = NULL;
Damien Millera8ed44b2003-01-10 09:53:12 +1100831
832#ifndef HAVE_SETPROCTITLE
833 /* Prepare for later setproctitle emulation */
834 compat_init_setproctitle(ac, av);
Damien Millerf2e3e9d2003-06-02 12:15:54 +1000835 av = saved_argv;
Damien Millera8ed44b2003-01-10 09:53:12 +1100836#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000837
Damien Miller95def091999-11-25 00:26:21 +1100838 /* Initialize configuration options to their default values. */
839 initialize_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000840
Damien Miller95def091999-11-25 00:26:21 +1100841 /* Parse command-line arguments. */
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000842 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqtQ46")) != -1) {
Damien Miller95def091999-11-25 00:26:21 +1100843 switch (opt) {
Damien Miller34132e52000-01-14 15:45:46 +1100844 case '4':
845 IPv4or6 = AF_INET;
846 break;
847 case '6':
848 IPv4or6 = AF_INET6;
849 break;
Damien Miller95def091999-11-25 00:26:21 +1100850 case 'f':
851 config_file_name = optarg;
852 break;
853 case 'd':
Darren Tuckere98dfa32003-07-19 19:54:31 +1000854 if (debug_flag == 0) {
Damien Millere4340be2000-09-16 13:29:08 +1100855 debug_flag = 1;
856 options.log_level = SYSLOG_LEVEL_DEBUG1;
Darren Tuckere98dfa32003-07-19 19:54:31 +1000857 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
Damien Millere4340be2000-09-16 13:29:08 +1100858 options.log_level++;
Damien Miller95def091999-11-25 00:26:21 +1100859 break;
Ben Lindstromc72745a2000-12-02 19:03:54 +0000860 case 'D':
861 no_daemon_flag = 1;
862 break;
Ben Lindstrom9fce9f02001-04-11 23:10:09 +0000863 case 'e':
864 log_stderr = 1;
865 break;
Damien Miller95def091999-11-25 00:26:21 +1100866 case 'i':
867 inetd_flag = 1;
868 break;
869 case 'Q':
Ben Lindstromd5390202001-01-29 08:07:43 +0000870 /* ignored */
Damien Miller95def091999-11-25 00:26:21 +1100871 break;
872 case 'q':
873 options.log_level = SYSLOG_LEVEL_QUIET;
874 break;
875 case 'b':
876 options.server_key_bits = atoi(optarg);
877 break;
878 case 'p':
Damien Miller34132e52000-01-14 15:45:46 +1100879 options.ports_from_cmdline = 1;
Damien Millere4340be2000-09-16 13:29:08 +1100880 if (options.num_ports >= MAX_PORTS) {
881 fprintf(stderr, "too many ports.\n");
882 exit(1);
883 }
Ben Lindstrom19066a12001-04-12 23:39:26 +0000884 options.ports[options.num_ports++] = a2port(optarg);
885 if (options.ports[options.num_ports-1] == 0) {
886 fprintf(stderr, "Bad port number.\n");
887 exit(1);
888 }
Damien Miller95def091999-11-25 00:26:21 +1100889 break;
890 case 'g':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +0000891 if ((options.login_grace_time = convtime(optarg)) == -1) {
892 fprintf(stderr, "Invalid login grace time.\n");
893 exit(1);
894 }
Damien Miller95def091999-11-25 00:26:21 +1100895 break;
896 case 'k':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +0000897 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
898 fprintf(stderr, "Invalid key regeneration interval.\n");
899 exit(1);
900 }
Damien Miller95def091999-11-25 00:26:21 +1100901 break;
902 case 'h':
Damien Miller0bc1bd82000-11-13 22:57:25 +1100903 if (options.num_host_key_files >= MAX_HOSTKEYS) {
904 fprintf(stderr, "too many host keys.\n");
905 exit(1);
906 }
907 options.host_key_files[options.num_host_key_files++] = optarg;
Damien Miller95def091999-11-25 00:26:21 +1100908 break;
Ben Lindstrom794325a2001-08-06 21:09:07 +0000909 case 't':
910 test_flag = 1;
911 break;
Damien Miller942da032000-08-18 13:59:06 +1000912 case 'u':
913 utmp_len = atoi(optarg);
Ben Lindstrom41daec72002-07-23 21:15:13 +0000914 if (utmp_len > MAXHOSTNAMELEN) {
915 fprintf(stderr, "Invalid utmp length.\n");
916 exit(1);
917 }
Damien Miller942da032000-08-18 13:59:06 +1000918 break;
Ben Lindstromade03f62001-12-06 18:22:17 +0000919 case 'o':
Damien Miller9f0f5c62001-12-21 14:45:46 +1100920 if (process_server_config_line(&options, optarg,
Ben Lindstromade03f62001-12-06 18:22:17 +0000921 "command-line", 0) != 0)
Damien Miller9f0f5c62001-12-21 14:45:46 +1100922 exit(1);
Ben Lindstromade03f62001-12-06 18:22:17 +0000923 break;
Damien Miller95def091999-11-25 00:26:21 +1100924 case '?':
925 default:
Ben Lindstromade03f62001-12-06 18:22:17 +0000926 usage();
927 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000928 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000929 }
Ben Lindstrom425fb022001-03-29 00:31:20 +0000930 SSLeay_add_all_algorithms();
Ben Lindstrom908afed2001-10-03 17:34:59 +0000931 channel_set_af(IPv4or6);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000932
Damien Miller34132e52000-01-14 15:45:46 +1100933 /*
934 * Force logging to stderr until we have loaded the private host
935 * key (unless started from inetd)
936 */
Kevin Stevesec84dc12000-12-13 17:45:15 +0000937 log_init(__progname,
Damien Miller5aa5d782002-02-08 22:01:54 +1100938 options.log_level == SYSLOG_LEVEL_NOT_SET ?
939 SYSLOG_LEVEL_INFO : options.log_level,
940 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
941 SYSLOG_FACILITY_AUTH : options.log_facility,
Ben Lindstromc2faa4a2002-11-09 15:50:03 +0000942 log_stderr || !inetd_flag);
Damien Miller34132e52000-01-14 15:45:46 +1100943
Tim Rice81ed5182002-09-25 17:38:46 -0700944#ifdef _UNICOS
Ben Lindstrom6db66ff2001-08-06 23:29:16 +0000945 /* Cray can define user privs drop all prives now!
946 * Not needed on PRIV_SU systems!
947 */
948 drop_cray_privs();
949#endif
950
Damien Miller60bc5172001-03-19 09:38:15 +1100951 seed_rng();
952
Damien Miller95def091999-11-25 00:26:21 +1100953 /* Read server configuration options from the configuration file. */
954 read_server_config(&options, config_file_name);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000955
Damien Miller95def091999-11-25 00:26:21 +1100956 /* Fill in default values for those options not explicitly set. */
957 fill_default_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000958
Damien Miller95def091999-11-25 00:26:21 +1100959 /* Check that there are no remaining arguments. */
960 if (optind < ac) {
961 fprintf(stderr, "Extra argument %s.\n", av[optind]);
962 exit(1);
963 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000964
Damien Miller95def091999-11-25 00:26:21 +1100965 debug("sshd version %.100s", SSH_VERSION);
Damien Miller2ccf6611999-11-15 15:25:10 +1100966
Damien Miller0bc1bd82000-11-13 22:57:25 +1100967 /* load private host keys */
Ben Lindstroma962c2f2002-07-04 00:14:17 +0000968 sensitive_data.host_keys = xmalloc(options.num_host_key_files *
969 sizeof(Key *));
Damien Miller9f0f5c62001-12-21 14:45:46 +1100970 for (i = 0; i < options.num_host_key_files; i++)
Ben Lindstrom46c16222000-12-22 01:43:59 +0000971 sensitive_data.host_keys[i] = NULL;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100972 sensitive_data.server_key = NULL;
973 sensitive_data.ssh1_host_key = NULL;
974 sensitive_data.have_ssh1_key = 0;
975 sensitive_data.have_ssh2_key = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000976
Damien Miller9f0f5c62001-12-21 14:45:46 +1100977 for (i = 0; i < options.num_host_key_files; i++) {
Ben Lindstromd0fca422001-03-26 13:44:06 +0000978 key = key_load_private(options.host_key_files[i], "", NULL);
979 sensitive_data.host_keys[i] = key;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100980 if (key == NULL) {
Ben Lindstrom15f33862001-04-16 02:00:02 +0000981 error("Could not load host key: %s",
982 options.host_key_files[i]);
Ben Lindstromd0fca422001-03-26 13:44:06 +0000983 sensitive_data.host_keys[i] = NULL;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100984 continue;
985 }
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000986 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100987 case KEY_RSA1:
988 sensitive_data.ssh1_host_key = key;
989 sensitive_data.have_ssh1_key = 1;
990 break;
991 case KEY_RSA:
992 case KEY_DSA:
993 sensitive_data.have_ssh2_key = 1;
994 break;
995 }
Ben Lindstromd0fca422001-03-26 13:44:06 +0000996 debug("private host key: #%d type %d %s", i, key->type,
997 key_type(key));
Damien Miller0bc1bd82000-11-13 22:57:25 +1100998 }
999 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001000 logit("Disabling protocol version 1. Could not load host key");
Damien Millereba71ba2000-04-29 23:57:08 +10001001 options.protocol &= ~SSH_PROTO_1;
1002 }
Damien Miller0bc1bd82000-11-13 22:57:25 +11001003 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001004 logit("Disabling protocol version 2. Could not load host key");
Damien Miller0bc1bd82000-11-13 22:57:25 +11001005 options.protocol &= ~SSH_PROTO_2;
Damien Millereba71ba2000-04-29 23:57:08 +10001006 }
Kevin Stevesadf74cd2001-02-05 14:22:50 +00001007 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
Damien Miller996acd22003-04-09 20:59:48 +10001008 logit("sshd: no hostkeys available -- exiting.");
Damien Miller95def091999-11-25 00:26:21 +11001009 exit(1);
1010 }
Damien Miller95def091999-11-25 00:26:21 +11001011
Damien Millereba71ba2000-04-29 23:57:08 +10001012 /* Check certain values for sanity. */
1013 if (options.protocol & SSH_PROTO_1) {
1014 if (options.server_key_bits < 512 ||
1015 options.server_key_bits > 32768) {
1016 fprintf(stderr, "Bad server key size.\n");
1017 exit(1);
1018 }
1019 /*
1020 * Check that server and host key lengths differ sufficiently. This
1021 * is necessary to make double encryption work with rsaref. Oh, I
1022 * hate software patents. I dont know if this can go? Niels
1023 */
1024 if (options.server_key_bits >
Ben Lindstrom822b6342002-06-23 21:38:49 +00001025 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1026 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1027 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1028 SSH_KEY_BITS_RESERVED) {
Damien Millereba71ba2000-04-29 23:57:08 +10001029 options.server_key_bits =
Ben Lindstrom822b6342002-06-23 21:38:49 +00001030 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1031 SSH_KEY_BITS_RESERVED;
Damien Millereba71ba2000-04-29 23:57:08 +10001032 debug("Forcing server key to %d bits to make it differ from host key.",
1033 options.server_key_bits);
1034 }
1035 }
1036
Ben Lindstroma26ea632002-06-06 20:46:25 +00001037 if (use_privsep) {
1038 struct passwd *pw;
1039 struct stat st;
1040
1041 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1042 fatal("Privilege separation user %s does not exist",
1043 SSH_PRIVSEP_USER);
1044 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1045 (S_ISDIR(st.st_mode) == 0))
1046 fatal("Missing privilege separation directory: %s",
1047 _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstrom59627352002-06-27 18:02:21 +00001048
1049#ifdef HAVE_CYGWIN
1050 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1051 (st.st_uid != getuid () ||
1052 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1053#else
Ben Lindstrom2dfacb32002-06-23 00:33:47 +00001054 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
Ben Lindstrom59627352002-06-27 18:02:21 +00001055#endif
Damien Miller180fc5b2003-02-24 11:50:18 +11001056 fatal("%s must be owned by root and not group or "
1057 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstroma26ea632002-06-06 20:46:25 +00001058 }
1059
Ben Lindstrom794325a2001-08-06 21:09:07 +00001060 /* Configuration looks good, so exit if in test mode. */
1061 if (test_flag)
1062 exit(0);
1063
Damien Miller87aea252002-05-10 12:20:24 +10001064 /*
1065 * Clear out any supplemental groups we may have inherited. This
1066 * prevents inadvertent creation of files with bad modes (in the
1067 * portable version at least, it's certainly possible for PAM
1068 * to create a file, and we can't control the code in every
1069 * module which might be used).
1070 */
1071 if (setgroups(0, NULL) < 0)
1072 debug("setgroups() failed: %.200s", strerror(errno));
1073
Damien Millereba71ba2000-04-29 23:57:08 +10001074 /* Initialize the log (it is reinitialized below in case we forked). */
Damien Miller95def091999-11-25 00:26:21 +11001075 if (debug_flag && !inetd_flag)
1076 log_stderr = 1;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001077 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001078
Damien Millereba71ba2000-04-29 23:57:08 +10001079 /*
1080 * If not in debugging mode, and not started from inetd, disconnect
1081 * from the controlling terminal, and fork. The original process
1082 * exits.
1083 */
Ben Lindstromc72745a2000-12-02 19:03:54 +00001084 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
Damien Miller95def091999-11-25 00:26:21 +11001085#ifdef TIOCNOTTY
1086 int fd;
1087#endif /* TIOCNOTTY */
1088 if (daemon(0, 0) < 0)
1089 fatal("daemon() failed: %.200s", strerror(errno));
1090
1091 /* Disconnect from the controlling tty. */
1092#ifdef TIOCNOTTY
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001093 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +11001094 if (fd >= 0) {
1095 (void) ioctl(fd, TIOCNOTTY, NULL);
1096 close(fd);
1097 }
1098#endif /* TIOCNOTTY */
1099 }
1100 /* Reinitialize the log (because of the fork above). */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001101 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001102
Damien Miller95def091999-11-25 00:26:21 +11001103 /* Initialize the random number generator. */
1104 arc4random_stir();
1105
1106 /* Chdir to the root directory so that the current disk can be
1107 unmounted if desired. */
1108 chdir("/");
Damien Miller9f0f5c62001-12-21 14:45:46 +11001109
Ben Lindstromde71cda2001-03-24 00:43:26 +00001110 /* ignore SIGPIPE */
1111 signal(SIGPIPE, SIG_IGN);
Damien Miller95def091999-11-25 00:26:21 +11001112
Damien Miller95def091999-11-25 00:26:21 +11001113 /* Start listening for a socket, unless started from inetd. */
1114 if (inetd_flag) {
Ben Lindstrom206941f2001-04-15 14:27:16 +00001115 int s1;
Damien Miller95def091999-11-25 00:26:21 +11001116 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
Ben Lindstrom206941f2001-04-15 14:27:16 +00001117 dup(s1);
Damien Miller95def091999-11-25 00:26:21 +11001118 sock_in = dup(0);
1119 sock_out = dup(1);
Damien Miller994cf142000-07-21 10:19:44 +10001120 startup_pipe = -1;
Damien Millereba71ba2000-04-29 23:57:08 +10001121 /*
1122 * We intentionally do not close the descriptors 0, 1, and 2
1123 * as our code for setting the descriptors won\'t work if
1124 * ttyfd happens to be one of those.
1125 */
Damien Miller95def091999-11-25 00:26:21 +11001126 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
Damien Miller0bc1bd82000-11-13 22:57:25 +11001127 if (options.protocol & SSH_PROTO_1)
Ben Lindstromca42d5f2001-03-09 18:25:32 +00001128 generate_ephemeral_server_key();
Damien Miller95def091999-11-25 00:26:21 +11001129 } else {
Damien Miller34132e52000-01-14 15:45:46 +11001130 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1131 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1132 continue;
1133 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1134 fatal("Too many listen sockets. "
1135 "Enlarge MAX_LISTEN_SOCKS");
1136 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
1137 ntop, sizeof(ntop), strport, sizeof(strport),
1138 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1139 error("getnameinfo failed");
1140 continue;
1141 }
1142 /* Create socket for listening. */
Damien Miller2372ace2003-05-14 13:42:23 +10001143 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1144 ai->ai_protocol);
Damien Miller34132e52000-01-14 15:45:46 +11001145 if (listen_sock < 0) {
1146 /* kernel may not support ipv6 */
1147 verbose("socket: %.100s", strerror(errno));
1148 continue;
1149 }
1150 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
1151 error("listen_sock O_NONBLOCK: %s", strerror(errno));
1152 close(listen_sock);
1153 continue;
1154 }
1155 /*
Damien Millere1383ce2002-09-19 11:49:37 +10001156 * Set socket options.
1157 * Allow local port reuse in TIME_WAIT.
Damien Miller34132e52000-01-14 15:45:46 +11001158 */
Damien Millere1383ce2002-09-19 11:49:37 +10001159 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1160 &on, sizeof(on)) == -1)
1161 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +11001162
Damien Miller34132e52000-01-14 15:45:46 +11001163 debug("Bind to port %s on %s.", strport, ntop);
Damien Miller95def091999-11-25 00:26:21 +11001164
Damien Miller34132e52000-01-14 15:45:46 +11001165 /* Bind the socket to the desired port. */
Damien Miller0a4e27d2001-02-18 12:36:39 +11001166 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1167 if (!ai->ai_next)
1168 error("Bind to port %s on %s failed: %.200s.",
1169 strport, ntop, strerror(errno));
Damien Miller34132e52000-01-14 15:45:46 +11001170 close(listen_sock);
1171 continue;
1172 }
1173 listen_socks[num_listen_socks] = listen_sock;
1174 num_listen_socks++;
Damien Miller95def091999-11-25 00:26:21 +11001175
Damien Miller34132e52000-01-14 15:45:46 +11001176 /* Start listening on the port. */
Damien Miller996acd22003-04-09 20:59:48 +10001177 logit("Server listening on %s port %s.", ntop, strport);
Damien Miller34132e52000-01-14 15:45:46 +11001178 if (listen(listen_sock, 5) < 0)
1179 fatal("listen: %.100s", strerror(errno));
1180
Damien Miller95def091999-11-25 00:26:21 +11001181 }
Damien Miller34132e52000-01-14 15:45:46 +11001182 freeaddrinfo(options.listen_addrs);
1183
1184 if (!num_listen_socks)
1185 fatal("Cannot bind any address.");
1186
Ben Lindstrom98097862001-06-25 05:10:20 +00001187 if (options.protocol & SSH_PROTO_1)
1188 generate_ephemeral_server_key();
1189
1190 /*
1191 * Arrange to restart on SIGHUP. The handler needs
1192 * listen_sock.
1193 */
1194 signal(SIGHUP, sighup_handler);
1195
1196 signal(SIGTERM, sigterm_handler);
1197 signal(SIGQUIT, sigterm_handler);
1198
1199 /* Arrange SIGCHLD to be caught. */
1200 signal(SIGCHLD, main_sigchld_handler);
1201
1202 /* Write out the pid file after the sigterm handler is setup */
Damien Miller95def091999-11-25 00:26:21 +11001203 if (!debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +11001204 /*
Ben Lindstrom7ad97102000-12-06 01:42:49 +00001205 * Record our pid in /var/run/sshd.pid to make it
1206 * easier to kill the correct sshd. We don't want to
1207 * do this before the bind above because the bind will
Damien Miller5428f641999-11-25 11:54:57 +11001208 * fail if there already is a daemon, and this will
1209 * overwrite any old pid in the file.
1210 */
Damien Millerbac2d8a2000-09-05 16:13:06 +11001211 f = fopen(options.pid_file, "wb");
Darren Tuckere5327042003-07-03 13:40:44 +10001212 if (f == NULL) {
1213 error("Couldn't create pid file \"%s\": %s",
1214 options.pid_file, strerror(errno));
1215 } else {
Ben Lindstromce0f6342002-06-11 16:42:49 +00001216 fprintf(f, "%ld\n", (long) getpid());
Damien Miller95def091999-11-25 00:26:21 +11001217 fclose(f);
1218 }
1219 }
Damien Miller95def091999-11-25 00:26:21 +11001220
Damien Miller34132e52000-01-14 15:45:46 +11001221 /* setup fd set for listen */
Damien Miller37023962000-07-11 17:31:38 +10001222 fdset = NULL;
Damien Miller34132e52000-01-14 15:45:46 +11001223 maxfd = 0;
1224 for (i = 0; i < num_listen_socks; i++)
1225 if (listen_socks[i] > maxfd)
1226 maxfd = listen_socks[i];
Damien Miller37023962000-07-11 17:31:38 +10001227 /* pipes connected to unauthenticated childs */
1228 startup_pipes = xmalloc(options.max_startups * sizeof(int));
1229 for (i = 0; i < options.max_startups; i++)
1230 startup_pipes[i] = -1;
Damien Miller34132e52000-01-14 15:45:46 +11001231
Damien Miller5428f641999-11-25 11:54:57 +11001232 /*
1233 * Stay listening for connections until the system crashes or
1234 * the daemon is killed with a signal.
1235 */
Damien Miller95def091999-11-25 00:26:21 +11001236 for (;;) {
1237 if (received_sighup)
1238 sighup_restart();
Damien Miller37023962000-07-11 17:31:38 +10001239 if (fdset != NULL)
1240 xfree(fdset);
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001241 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
Damien Miller37023962000-07-11 17:31:38 +10001242 fdset = (fd_set *)xmalloc(fdsetsz);
Damien Miller34132e52000-01-14 15:45:46 +11001243 memset(fdset, 0, fdsetsz);
Damien Miller37023962000-07-11 17:31:38 +10001244
Damien Miller34132e52000-01-14 15:45:46 +11001245 for (i = 0; i < num_listen_socks; i++)
1246 FD_SET(listen_socks[i], fdset);
Damien Miller37023962000-07-11 17:31:38 +10001247 for (i = 0; i < options.max_startups; i++)
1248 if (startup_pipes[i] != -1)
1249 FD_SET(startup_pipes[i], fdset);
1250
1251 /* Wait in select until there is a connection. */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001252 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1253 if (ret < 0 && errno != EINTR)
1254 error("select: %.100s", strerror(errno));
Ben Lindstromec46e0b2001-06-09 01:27:31 +00001255 if (received_sigterm) {
Damien Miller996acd22003-04-09 20:59:48 +10001256 logit("Received signal %d; terminating.",
Ben Lindstromf8f065b2001-12-06 17:52:16 +00001257 (int) received_sigterm);
Ben Lindstromec46e0b2001-06-09 01:27:31 +00001258 close_listen_socks();
1259 unlink(options.pid_file);
1260 exit(255);
1261 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001262 if (key_used && key_do_regen) {
Ben Lindstromca42d5f2001-03-09 18:25:32 +00001263 generate_ephemeral_server_key();
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001264 key_used = 0;
1265 key_do_regen = 0;
Damien Miller34132e52000-01-14 15:45:46 +11001266 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001267 if (ret < 0)
1268 continue;
1269
Damien Miller37023962000-07-11 17:31:38 +10001270 for (i = 0; i < options.max_startups; i++)
1271 if (startup_pipes[i] != -1 &&
1272 FD_ISSET(startup_pipes[i], fdset)) {
1273 /*
1274 * the read end of the pipe is ready
1275 * if the child has closed the pipe
Ben Lindstrom4dccfa52000-12-28 16:40:05 +00001276 * after successful authentication
Damien Miller37023962000-07-11 17:31:38 +10001277 * or if the child has died
1278 */
1279 close(startup_pipes[i]);
1280 startup_pipes[i] = -1;
1281 startups--;
1282 }
Damien Miller34132e52000-01-14 15:45:46 +11001283 for (i = 0; i < num_listen_socks; i++) {
1284 if (!FD_ISSET(listen_socks[i], fdset))
Damien Miller95def091999-11-25 00:26:21 +11001285 continue;
Damien Miller37023962000-07-11 17:31:38 +10001286 fromlen = sizeof(from);
1287 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1288 &fromlen);
1289 if (newsock < 0) {
1290 if (errno != EINTR && errno != EWOULDBLOCK)
1291 error("accept: %.100s", strerror(errno));
1292 continue;
1293 }
1294 if (fcntl(newsock, F_SETFL, 0) < 0) {
1295 error("newsock del O_NONBLOCK: %s", strerror(errno));
Damien Miller72c336d2001-12-21 12:44:28 +11001296 close(newsock);
Damien Miller37023962000-07-11 17:31:38 +10001297 continue;
1298 }
Damien Miller942da032000-08-18 13:59:06 +10001299 if (drop_connection(startups) == 1) {
1300 debug("drop connection #%d", startups);
Damien Miller37023962000-07-11 17:31:38 +10001301 close(newsock);
1302 continue;
1303 }
1304 if (pipe(startup_p) == -1) {
1305 close(newsock);
1306 continue;
1307 }
1308
1309 for (j = 0; j < options.max_startups; j++)
1310 if (startup_pipes[j] == -1) {
1311 startup_pipes[j] = startup_p[0];
1312 if (maxfd < startup_p[0])
1313 maxfd = startup_p[0];
1314 startups++;
1315 break;
1316 }
Kevin Stevesef4eea92001-02-05 12:42:17 +00001317
Damien Miller5428f641999-11-25 11:54:57 +11001318 /*
Damien Miller37023962000-07-11 17:31:38 +10001319 * Got connection. Fork a child to handle it, unless
1320 * we are in debugging mode.
Damien Miller5428f641999-11-25 11:54:57 +11001321 */
Damien Miller37023962000-07-11 17:31:38 +10001322 if (debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +11001323 /*
Damien Miller37023962000-07-11 17:31:38 +10001324 * In debugging mode. Close the listening
1325 * socket, and start processing the
1326 * connection without forking.
Damien Miller5428f641999-11-25 11:54:57 +11001327 */
Damien Miller37023962000-07-11 17:31:38 +10001328 debug("Server will not fork when running in debugging mode.");
Damien Miller34132e52000-01-14 15:45:46 +11001329 close_listen_socks();
Damien Miller95def091999-11-25 00:26:21 +11001330 sock_in = newsock;
1331 sock_out = newsock;
Damien Miller4d97ba22000-07-11 18:15:50 +10001332 startup_pipe = -1;
Damien Miller182ee6e2000-07-12 09:45:27 +10001333 pid = getpid();
Damien Miller95def091999-11-25 00:26:21 +11001334 break;
Damien Miller37023962000-07-11 17:31:38 +10001335 } else {
1336 /*
1337 * Normal production daemon. Fork, and have
1338 * the child process the connection. The
1339 * parent continues listening.
1340 */
1341 if ((pid = fork()) == 0) {
1342 /*
1343 * Child. Close the listening and max_startup
1344 * sockets. Start using the accepted socket.
1345 * Reinitialize logging (since our pid has
1346 * changed). We break out of the loop to handle
1347 * the connection.
1348 */
1349 startup_pipe = startup_p[1];
Ben Lindstromd84df982001-12-06 16:35:40 +00001350 close_startup_pipes();
Damien Miller37023962000-07-11 17:31:38 +10001351 close_listen_socks();
1352 sock_in = newsock;
1353 sock_out = newsock;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001354 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller37023962000-07-11 17:31:38 +10001355 break;
1356 }
Damien Miller95def091999-11-25 00:26:21 +11001357 }
Damien Miller37023962000-07-11 17:31:38 +10001358
1359 /* Parent. Stay in the loop. */
1360 if (pid < 0)
1361 error("fork: %.100s", strerror(errno));
1362 else
Ben Lindstromce0f6342002-06-11 16:42:49 +00001363 debug("Forked child %ld.", (long)pid);
Damien Miller37023962000-07-11 17:31:38 +10001364
1365 close(startup_p[1]);
1366
1367 /* Mark that the key has been used (it was "given" to the child). */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001368 if ((options.protocol & SSH_PROTO_1) &&
1369 key_used == 0) {
1370 /* Schedule server key regeneration alarm. */
Ben Lindstrom5ade9ab2003-08-25 01:16:21 +00001371 signal(SIGALRM, key_regeneration_alarm);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001372 alarm(options.key_regeneration_time);
1373 key_used = 1;
1374 }
Damien Miller37023962000-07-11 17:31:38 +10001375
1376 arc4random_stir();
1377
1378 /* Close the new socket (the child is now taking care of it). */
1379 close(newsock);
Damien Miller95def091999-11-25 00:26:21 +11001380 }
Damien Miller34132e52000-01-14 15:45:46 +11001381 /* child process check (or debug mode) */
1382 if (num_listen_socks < 0)
1383 break;
Damien Miller95def091999-11-25 00:26:21 +11001384 }
1385 }
1386
1387 /* This is the child processing a new connection. */
1388
Damien Miller5428f641999-11-25 11:54:57 +11001389 /*
Ben Lindstrom17401b62002-05-15 16:17:56 +00001390 * Create a new session and process group since the 4.4BSD
1391 * setlogin() affects the entire process group. We don't
1392 * want the child to be able to affect the parent.
1393 */
Darren Tuckerc437cda2003-05-10 17:05:46 +10001394#if !defined(SSHD_ACQUIRES_CTTY)
Damien Miller933cc8f2003-03-10 11:38:10 +11001395 /*
Darren Tuckerc437cda2003-05-10 17:05:46 +10001396 * If setsid is called, on some platforms sshd will later acquire a
1397 * controlling terminal which will result in "could not set
1398 * controlling tty" errors.
Damien Miller933cc8f2003-03-10 11:38:10 +11001399 */
Ben Lindstrom57f08002002-06-23 00:37:10 +00001400 if (!debug_flag && !inetd_flag && setsid() < 0)
Ben Lindstrom17401b62002-05-15 16:17:56 +00001401 error("setsid: %.100s", strerror(errno));
Kevin Stevesc5041ac2002-05-21 17:50:21 +00001402#endif
Ben Lindstrom17401b62002-05-15 16:17:56 +00001403
1404 /*
Damien Miller5428f641999-11-25 11:54:57 +11001405 * Disable the key regeneration alarm. We will not regenerate the
1406 * key since we are no longer in a position to give it to anyone. We
1407 * will not restart on SIGHUP since it no longer makes sense.
1408 */
Damien Miller95def091999-11-25 00:26:21 +11001409 alarm(0);
1410 signal(SIGALRM, SIG_DFL);
1411 signal(SIGHUP, SIG_DFL);
1412 signal(SIGTERM, SIG_DFL);
1413 signal(SIGQUIT, SIG_DFL);
1414 signal(SIGCHLD, SIG_DFL);
Damien Miller4e0f5e12000-08-29 11:05:50 +11001415 signal(SIGINT, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +11001416
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001417 /* Set keepalives if requested. */
1418 if (options.keepalives &&
Ben Lindstrom733a2352002-03-05 01:31:28 +00001419 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001420 sizeof(on)) < 0)
1421 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1422
Damien Miller5428f641999-11-25 11:54:57 +11001423 /*
1424 * Register our connection. This turns encryption off because we do
1425 * not have a key.
1426 */
Damien Miller95def091999-11-25 00:26:21 +11001427 packet_set_connection(sock_in, sock_out);
1428
1429 remote_port = get_remote_port();
1430 remote_ip = get_remote_ipaddr();
1431
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001432#ifdef LIBWRAP
Damien Miller6a4a4b92001-11-12 11:07:11 +11001433 /* Check whether logins are denied from this host. */
Damien Miller95def091999-11-25 00:26:21 +11001434 {
1435 struct request_info req;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001436
Ben Lindstromce89dac2001-09-12 16:58:04 +00001437 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
Damien Miller95def091999-11-25 00:26:21 +11001438 fromhost(&req);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001439
Damien Miller95def091999-11-25 00:26:21 +11001440 if (!hosts_access(&req)) {
Damien Miller6a4a4b92001-11-12 11:07:11 +11001441 debug("Connection refused by tcp wrapper");
Ben Lindstrom7de696e2001-03-29 00:45:12 +00001442 refuse(&req);
Damien Miller6a4a4b92001-11-12 11:07:11 +11001443 /* NOTREACHED */
1444 fatal("libwrap refuse returns");
Damien Miller95def091999-11-25 00:26:21 +11001445 }
Damien Miller95def091999-11-25 00:26:21 +11001446 }
Damien Miller34132e52000-01-14 15:45:46 +11001447#endif /* LIBWRAP */
Damien Miller6a4a4b92001-11-12 11:07:11 +11001448
Damien Miller95def091999-11-25 00:26:21 +11001449 /* Log the connection. */
1450 verbose("Connection from %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001451
Damien Miller5428f641999-11-25 11:54:57 +11001452 /*
1453 * We don\'t want to listen forever unless the other side
1454 * successfully authenticates itself. So we set up an alarm which is
1455 * cleared after successful authentication. A limit of zero
1456 * indicates no limit. Note that we don\'t set the alarm in debugging
1457 * mode; it is just annoying to have the server exit just when you
1458 * are about to discover the bug.
1459 */
Ben Lindstrom5ade9ab2003-08-25 01:16:21 +00001460 signal(SIGALRM, grace_alarm_handler);
Damien Miller95def091999-11-25 00:26:21 +11001461 if (!debug_flag)
1462 alarm(options.login_grace_time);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001463
Damien Millerb38eff82000-04-01 11:09:21 +10001464 sshd_exchange_identification(sock_in, sock_out);
Darren Tuckerec960f22003-08-13 20:37:05 +10001465
Darren Tucker6aaa58c2003-08-02 22:24:49 +10001466#ifdef KRB5
Damien Miller34132e52000-01-14 15:45:46 +11001467 if (!packet_connection_is_ipv4() &&
1468 options.kerberos_authentication) {
1469 debug("Kerberos Authentication disabled, only available for IPv4.");
1470 options.kerberos_authentication = 0;
1471 }
Darren Tucker6aaa58c2003-08-02 22:24:49 +10001472#endif
Damien Miller34132e52000-01-14 15:45:46 +11001473
Damien Miller95def091999-11-25 00:26:21 +11001474 packet_set_nonblocking();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001475
Darren Tuckerb9aa0a02003-07-08 22:59:59 +10001476 /* prepare buffers to collect authentication messages */
1477 buffer_init(&loginmsg);
1478
Ben Lindstrom943481c2002-03-22 03:43:46 +00001479 if (use_privsep)
1480 if ((authctxt = privsep_preauth()) != NULL)
1481 goto authenticated;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001482
Damien Miller396691a2000-01-20 22:44:08 +11001483 /* perform the key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001484 /* authenticate user and start session */
Damien Millerefb4afe2000-04-12 18:45:05 +10001485 if (compat20) {
1486 do_ssh2_kex();
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001487 authctxt = do_authentication2();
Damien Millerefb4afe2000-04-12 18:45:05 +10001488 } else {
1489 do_ssh1_kex();
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001490 authctxt = do_authentication();
Damien Millerefb4afe2000-04-12 18:45:05 +10001491 }
Ben Lindstrom943481c2002-03-22 03:43:46 +00001492 /*
1493 * If we use privilege separation, the unprivileged child transfers
1494 * the current keystate and exits
1495 */
1496 if (use_privsep) {
Ben Lindstrom7339b2a2002-05-15 16:25:01 +00001497 mm_send_keystate(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001498 exit(0);
Ben Lindstrom943481c2002-03-22 03:43:46 +00001499 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001500
1501 authenticated:
Ben Lindstrom6328ab32002-03-22 02:54:23 +00001502 /*
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001503 * In privilege separation, we fork another child and prepare
1504 * file descriptor passing.
1505 */
1506 if (use_privsep) {
Ben Lindstrom943481c2002-03-22 03:43:46 +00001507 privsep_postauth(authctxt);
1508 /* the monitor process [priv] will not return */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001509 if (!compat20)
1510 destroy_sensitive_data();
1511 }
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001512
1513 /* Perform session preparation. */
1514 do_authenticated(authctxt);
1515
Damien Miller3a5b0232002-03-13 13:19:42 +11001516 /* The connection has been terminated. */
1517 verbose("Closing connection to %.100s", remote_ip);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001518
Damien Millerbeb4ba51999-12-28 15:09:35 +11001519#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +10001520 if (options.use_pam)
1521 finish_pam();
Damien Millerbeb4ba51999-12-28 15:09:35 +11001522#endif /* USE_PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001523
Damien Miller95def091999-11-25 00:26:21 +11001524 packet_close();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001525
1526 if (use_privsep)
1527 mm_terminate();
1528
Damien Miller95def091999-11-25 00:26:21 +11001529 exit(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001530}
1531
Damien Miller95def091999-11-25 00:26:21 +11001532/*
Ben Lindstromabcb1452002-03-22 01:10:21 +00001533 * Decrypt session_key_int using our private server key and private host key
1534 * (key with larger modulus first).
1535 */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001536int
Ben Lindstromabcb1452002-03-22 01:10:21 +00001537ssh1_session_key(BIGNUM *session_key_int)
1538{
1539 int rsafail = 0;
1540
1541 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
1542 /* Server key has bigger modulus. */
1543 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1544 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1545 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1546 get_remote_ipaddr(),
1547 BN_num_bits(sensitive_data.server_key->rsa->n),
1548 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1549 SSH_KEY_BITS_RESERVED);
1550 }
1551 if (rsa_private_decrypt(session_key_int, session_key_int,
1552 sensitive_data.server_key->rsa) <= 0)
1553 rsafail++;
1554 if (rsa_private_decrypt(session_key_int, session_key_int,
1555 sensitive_data.ssh1_host_key->rsa) <= 0)
1556 rsafail++;
1557 } else {
1558 /* Host key has bigger modulus (or they are equal). */
1559 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1560 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1561 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1562 get_remote_ipaddr(),
1563 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1564 BN_num_bits(sensitive_data.server_key->rsa->n),
1565 SSH_KEY_BITS_RESERVED);
1566 }
1567 if (rsa_private_decrypt(session_key_int, session_key_int,
1568 sensitive_data.ssh1_host_key->rsa) < 0)
1569 rsafail++;
1570 if (rsa_private_decrypt(session_key_int, session_key_int,
1571 sensitive_data.server_key->rsa) < 0)
1572 rsafail++;
1573 }
1574 return (rsafail);
1575}
1576/*
Damien Miller396691a2000-01-20 22:44:08 +11001577 * SSH1 key exchange
Damien Miller95def091999-11-25 00:26:21 +11001578 */
Ben Lindstrombba81212001-06-25 05:01:22 +00001579static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001580do_ssh1_kex(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001581{
Damien Miller95def091999-11-25 00:26:21 +11001582 int i, len;
Damien Miller7650bc62001-01-30 09:27:26 +11001583 int rsafail = 0;
Damien Miller95def091999-11-25 00:26:21 +11001584 BIGNUM *session_key_int;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001585 u_char session_key[SSH_SESSION_KEY_LENGTH];
1586 u_char cookie[8];
1587 u_int cipher_type, auth_mask, protocol_flags;
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001588 u_int32_t rnd = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001589
Damien Miller5428f641999-11-25 11:54:57 +11001590 /*
1591 * Generate check bytes that the client must send back in the user
1592 * packet in order for it to be accepted; this is used to defy ip
1593 * spoofing attacks. Note that this only works against somebody
1594 * doing IP spoofing from a remote machine; any machine on the local
1595 * network can still see outgoing packets and catch the random
1596 * cookie. This only affects rhosts authentication, and this is one
1597 * of the reasons why it is inherently insecure.
1598 */
Damien Miller95def091999-11-25 00:26:21 +11001599 for (i = 0; i < 8; i++) {
1600 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001601 rnd = arc4random();
1602 cookie[i] = rnd & 0xff;
1603 rnd >>= 8;
Damien Miller95def091999-11-25 00:26:21 +11001604 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001605
Damien Miller5428f641999-11-25 11:54:57 +11001606 /*
1607 * Send our public key. We include in the packet 64 bits of random
1608 * data that must be matched in the reply in order to prevent IP
1609 * spoofing.
1610 */
Damien Miller95def091999-11-25 00:26:21 +11001611 packet_start(SSH_SMSG_PUBLIC_KEY);
1612 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001613 packet_put_char(cookie[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001614
Damien Miller95def091999-11-25 00:26:21 +11001615 /* Store our public server RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001616 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1617 packet_put_bignum(sensitive_data.server_key->rsa->e);
1618 packet_put_bignum(sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001619
Damien Miller95def091999-11-25 00:26:21 +11001620 /* Store our public host RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001621 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1622 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1623 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001624
Damien Miller95def091999-11-25 00:26:21 +11001625 /* Put protocol flags. */
1626 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001627
Damien Miller95def091999-11-25 00:26:21 +11001628 /* Declare which ciphers we support. */
Damien Miller874d77b2000-10-14 16:23:11 +11001629 packet_put_int(cipher_mask_ssh1(0));
Damien Miller95def091999-11-25 00:26:21 +11001630
1631 /* Declare supported authentication types. */
1632 auth_mask = 0;
Damien Miller95def091999-11-25 00:26:21 +11001633 if (options.rhosts_rsa_authentication)
1634 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1635 if (options.rsa_authentication)
1636 auth_mask |= 1 << SSH_AUTH_RSA;
Darren Tucker6aaa58c2003-08-02 22:24:49 +10001637#ifdef KRB5
Damien Miller95def091999-11-25 00:26:21 +11001638 if (options.kerberos_authentication)
1639 auth_mask |= 1 << SSH_AUTH_KERBEROS;
Damien Miller95def091999-11-25 00:26:21 +11001640 if (options.kerberos_tgt_passing)
1641 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
Ben Lindstromec95ed92001-07-04 04:21:14 +00001642#endif
Ben Lindstrom551ea372001-06-05 18:56:16 +00001643 if (options.challenge_response_authentication == 1)
Damien Miller95def091999-11-25 00:26:21 +11001644 auth_mask |= 1 << SSH_AUTH_TIS;
Damien Miller95def091999-11-25 00:26:21 +11001645 if (options.password_authentication)
1646 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1647 packet_put_int(auth_mask);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001648
Damien Miller95def091999-11-25 00:26:21 +11001649 /* Send the packet and wait for it to be sent. */
1650 packet_send();
1651 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001652
Damien Miller0bc1bd82000-11-13 22:57:25 +11001653 debug("Sent %d bit server key and %d bit host key.",
1654 BN_num_bits(sensitive_data.server_key->rsa->n),
1655 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001656
Damien Miller95def091999-11-25 00:26:21 +11001657 /* Read clients reply (cipher type and session key). */
Damien Millerdff50992002-01-22 23:16:32 +11001658 packet_read_expect(SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001659
Damien Miller50945fa1999-12-09 10:31:37 +11001660 /* Get cipher type and check whether we accept this. */
Damien Miller95def091999-11-25 00:26:21 +11001661 cipher_type = packet_get_char();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001662
Damien Miller874d77b2000-10-14 16:23:11 +11001663 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
Damien Miller50945fa1999-12-09 10:31:37 +11001664 packet_disconnect("Warning: client selects unsupported cipher.");
1665
Damien Miller95def091999-11-25 00:26:21 +11001666 /* Get check bytes from the packet. These must match those we
1667 sent earlier with the public key packet. */
1668 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001669 if (cookie[i] != packet_get_char())
Damien Miller95def091999-11-25 00:26:21 +11001670 packet_disconnect("IP Spoofing check bytes do not match.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001671
Damien Miller95def091999-11-25 00:26:21 +11001672 debug("Encryption type: %.200s", cipher_name(cipher_type));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001673
Damien Miller95def091999-11-25 00:26:21 +11001674 /* Get the encrypted integer. */
Damien Millerda755162002-01-22 23:09:22 +11001675 if ((session_key_int = BN_new()) == NULL)
1676 fatal("do_ssh1_kex: BN_new failed");
Damien Millerd432ccf2002-01-22 23:14:44 +11001677 packet_get_bignum(session_key_int);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001678
Damien Miller95def091999-11-25 00:26:21 +11001679 protocol_flags = packet_get_int();
1680 packet_set_protocol_flags(protocol_flags);
Damien Miller48b03fc2002-01-22 23:11:40 +11001681 packet_check_eom();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001682
Ben Lindstromabcb1452002-03-22 01:10:21 +00001683 /* Decrypt session_key_int using host/server keys */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001684 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1685
Damien Miller5428f641999-11-25 11:54:57 +11001686 /*
1687 * Extract session key from the decrypted integer. The key is in the
1688 * least significant 256 bits of the integer; the first byte of the
1689 * key is in the highest bits.
1690 */
Damien Miller7650bc62001-01-30 09:27:26 +11001691 if (!rsafail) {
1692 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1693 len = BN_num_bytes(session_key_int);
1694 if (len < 0 || len > sizeof(session_key)) {
1695 error("do_connection: bad session key len from %s: "
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001696 "session_key_int %d > sizeof(session_key) %lu",
1697 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
Damien Miller7650bc62001-01-30 09:27:26 +11001698 rsafail++;
1699 } else {
1700 memset(session_key, 0, sizeof(session_key));
1701 BN_bn2bin(session_key_int,
1702 session_key + sizeof(session_key) - len);
Ben Lindstromeb648a72001-03-05 06:00:29 +00001703
1704 compute_session_id(session_id, cookie,
1705 sensitive_data.ssh1_host_key->rsa->n,
1706 sensitive_data.server_key->rsa->n);
1707 /*
1708 * Xor the first 16 bytes of the session key with the
1709 * session id.
1710 */
1711 for (i = 0; i < 16; i++)
1712 session_key[i] ^= session_id[i];
Damien Miller7650bc62001-01-30 09:27:26 +11001713 }
1714 }
1715 if (rsafail) {
Ben Lindstromeb648a72001-03-05 06:00:29 +00001716 int bytes = BN_num_bytes(session_key_int);
Ben Lindstrom13c5d3b2002-02-26 18:00:48 +00001717 u_char *buf = xmalloc(bytes);
Ben Lindstromeb648a72001-03-05 06:00:29 +00001718 MD5_CTX md;
1719
Damien Miller996acd22003-04-09 20:59:48 +10001720 logit("do_connection: generating a fake encryption key");
Ben Lindstromeb648a72001-03-05 06:00:29 +00001721 BN_bn2bin(session_key_int, buf);
1722 MD5_Init(&md);
1723 MD5_Update(&md, buf, bytes);
1724 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1725 MD5_Final(session_key, &md);
1726 MD5_Init(&md);
1727 MD5_Update(&md, session_key, 16);
1728 MD5_Update(&md, buf, bytes);
1729 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1730 MD5_Final(session_key + 16, &md);
1731 memset(buf, 0, bytes);
1732 xfree(buf);
Ben Lindstrom941ac822001-03-05 06:25:23 +00001733 for (i = 0; i < 16; i++)
1734 session_id[i] = session_key[i] ^ session_key[i + 16];
Damien Miller7650bc62001-01-30 09:27:26 +11001735 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001736 /* Destroy the private and public keys. No longer. */
Damien Miller3a5b0232002-03-13 13:19:42 +11001737 destroy_sensitive_data();
Ben Lindstromeb648a72001-03-05 06:00:29 +00001738
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001739 if (use_privsep)
1740 mm_ssh1_session_id(session_id);
1741
Damien Miller396691a2000-01-20 22:44:08 +11001742 /* Destroy the decrypted integer. It is no longer needed. */
1743 BN_clear_free(session_key_int);
1744
Damien Miller95def091999-11-25 00:26:21 +11001745 /* Set the session key. From this on all communications will be encrypted. */
1746 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001747
Damien Miller95def091999-11-25 00:26:21 +11001748 /* Destroy our copy of the session key. It is no longer needed. */
1749 memset(session_key, 0, sizeof(session_key));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001750
Damien Miller95def091999-11-25 00:26:21 +11001751 debug("Received session key; encryption turned on.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001752
Ben Lindstromf666fec2002-06-06 19:51:58 +00001753 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
Damien Miller95def091999-11-25 00:26:21 +11001754 packet_start(SSH_SMSG_SUCCESS);
1755 packet_send();
1756 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001757}
Damien Millerefb4afe2000-04-12 18:45:05 +10001758
1759/*
1760 * SSH2 key exchange: diffie-hellman-group1-sha1
1761 */
Ben Lindstrombba81212001-06-25 05:01:22 +00001762static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001763do_ssh2_kex(void)
Damien Millerefb4afe2000-04-12 18:45:05 +10001764{
Damien Millerefb4afe2000-04-12 18:45:05 +10001765 Kex *kex;
Damien Millerefb4afe2000-04-12 18:45:05 +10001766
Damien Miller78928792000-04-12 20:17:38 +10001767 if (options.ciphers != NULL) {
Damien Miller4af51302000-04-16 11:18:38 +10001768 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
Damien Miller78928792000-04-12 20:17:38 +10001769 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1770 }
Damien Millera0ff4662001-03-30 10:49:35 +10001771 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1772 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
1773 myproposal[PROPOSAL_ENC_ALGS_STOC] =
1774 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1775
Ben Lindstrom06b33aa2001-02-15 03:01:59 +00001776 if (options.macs != NULL) {
1777 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1778 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1779 }
Ben Lindstrom23e0f662002-06-21 01:09:47 +00001780 if (!options.compression) {
1781 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1782 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1783 }
Damien Miller0bc1bd82000-11-13 22:57:25 +11001784 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1785
Ben Lindstrom8ac91062001-04-04 17:57:54 +00001786 /* start key exchange */
Ben Lindstrom238abf62001-04-04 17:52:53 +00001787 kex = kex_setup(myproposal);
Damien Miller8e7fb332003-02-24 12:03:03 +11001788 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1789 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00001790 kex->server = 1;
1791 kex->client_version_string=client_version_string;
1792 kex->server_version_string=server_version_string;
1793 kex->load_host_key=&get_hostkey_by_type;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001794 kex->host_key_index=&get_hostkey_index;
Damien Millerefb4afe2000-04-12 18:45:05 +10001795
Ben Lindstrom8ac91062001-04-04 17:57:54 +00001796 xxx_kex = kex;
1797
Ben Lindstrombe2cc432001-04-04 23:46:07 +00001798 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
Damien Miller874d77b2000-10-14 16:23:11 +11001799
Ben Lindstrom2d90e002001-04-04 02:00:54 +00001800 session_id2 = kex->session_id;
1801 session_id2_len = kex->session_id_len;
1802
Damien Miller874d77b2000-10-14 16:23:11 +11001803#ifdef DEBUG_KEXDH
1804 /* send 1st encrypted/maced/compressed message */
1805 packet_start(SSH2_MSG_IGNORE);
1806 packet_put_cstring("markus");
1807 packet_send();
1808 packet_write_wait();
1809#endif
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00001810 debug("KEX done");
Damien Millerefb4afe2000-04-12 18:45:05 +10001811}