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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"
Damien Miller9cf6d072006-03-15 11:29:24 +110045RCSID("$OpenBSD: sshd.c,v 1.321 2006/02/10 01:44:27 stevesk Exp $");
Damien Miller17e91c02006-03-15 11:28:34 +110046
47#include <sys/ioctl.h>
Damien Miller9cf6d072006-03-15 11:29:24 +110048#include <sys/types.h>
49#include <sys/wait.h>
Damien Miller03e20032006-03-15 11:16:59 +110050
51#include <paths.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100052
Ben Lindstrom226cfa02001-01-22 05:34:40 +000053#include <openssl/dh.h>
54#include <openssl/bn.h>
Damien Miller6a47f302002-02-13 13:55:06 +110055#include <openssl/md5.h>
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000056#include <openssl/rand.h>
Kevin Steves0ea1d9d2002-04-25 18:17:04 +000057#ifdef HAVE_SECUREWARE
58#include <sys/security.h>
59#include <prot.h>
60#endif
Ben Lindstrom226cfa02001-01-22 05:34:40 +000061
62#include "ssh.h"
63#include "ssh1.h"
64#include "ssh2.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100065#include "xmalloc.h"
66#include "rsa.h"
Ben Lindstromd95c09c2001-02-18 19:13:33 +000067#include "sshpty.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100068#include "packet.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000069#include "log.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100070#include "servconf.h"
71#include "uidswap.h"
72#include "compat.h"
Damien Millerb38eff82000-04-01 11:09:21 +100073#include "buffer.h"
Darren Tucker645ab752004-06-25 13:33:20 +100074#include "bufaux.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000075#include "cipher.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100076#include "kex.h"
Damien Millerb38eff82000-04-01 11:09:21 +100077#include "key.h"
Damien Miller874d77b2000-10-14 16:23:11 +110078#include "dh.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100079#include "myproposal.h"
Damien Millereba71ba2000-04-29 23:57:08 +100080#include "authfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000081#include "pathnames.h"
82#include "atomicio.h"
83#include "canohost.h"
84#include "auth.h"
85#include "misc.h"
Darren Tucker645ab752004-06-25 13:33:20 +100086#include "msg.h"
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +000087#include "dispatch.h"
Ben Lindstrom1bae4042001-10-03 17:46:39 +000088#include "channels.h"
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +000089#include "session.h"
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000090#include "monitor_mm.h"
91#include "monitor.h"
92#include "monitor_wrap.h"
93#include "monitor_fdpass.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100094
95#ifdef LIBWRAP
96#include <tcpd.h>
97#include <syslog.h>
98int allow_severity = LOG_INFO;
99int deny_severity = LOG_WARNING;
100#endif /* LIBWRAP */
101
102#ifndef O_NOCTTY
103#define O_NOCTTY 0
104#endif
105
Damien Miller035a5b42004-06-26 08:16:31 +1000106/* Re-exec fds */
107#define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
108#define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
109#define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
110#define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
111
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000112extern char *__progname;
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000113
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000114/* Server configuration options. */
115ServerOptions options;
116
117/* Name of the server configuration file. */
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000118char *config_file_name = _PATH_SERVER_CONFIG_FILE;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000119
Damien Miller4af51302000-04-16 11:18:38 +1000120/*
Damien Miller95def091999-11-25 00:26:21 +1100121 * Debug mode flag. This can be set on the command line. If debug
122 * mode is enabled, extra debugging output will be sent to the system
123 * log, the daemon will not go to background, and will exit after processing
124 * the first connection.
125 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000126int debug_flag = 0;
127
Ben Lindstrom794325a2001-08-06 21:09:07 +0000128/* Flag indicating that the daemon should only test the configuration and keys. */
129int test_flag = 0;
130
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000131/* Flag indicating that the daemon is being started from inetd. */
132int inetd_flag = 0;
133
Ben Lindstromc72745a2000-12-02 19:03:54 +0000134/* Flag indicating that sshd should not detach and become a daemon. */
135int no_daemon_flag = 0;
136
Damien Miller5ce662a1999-11-11 17:57:39 +1100137/* debug goes to stderr unless inetd_flag is set */
138int log_stderr = 0;
139
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000140/* Saved arguments to main(). */
141char **saved_argv;
Damien Millerb8c656e2000-06-28 15:22:41 +1000142int saved_argc;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000143
Darren Tucker645ab752004-06-25 13:33:20 +1000144/* re-exec */
145int rexeced_flag = 0;
146int rexec_flag = 1;
147int rexec_argc = 0;
148char **rexec_argv;
149
Damien Miller5428f641999-11-25 11:54:57 +1100150/*
Damien Miller34132e52000-01-14 15:45:46 +1100151 * The sockets that the server is listening; this is used in the SIGHUP
152 * signal handler.
Damien Miller5428f641999-11-25 11:54:57 +1100153 */
Damien Miller34132e52000-01-14 15:45:46 +1100154#define MAX_LISTEN_SOCKS 16
155int listen_socks[MAX_LISTEN_SOCKS];
156int num_listen_socks = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000157
Damien Miller5428f641999-11-25 11:54:57 +1100158/*
159 * the client's version string, passed by sshd2 in compat mode. if != NULL,
160 * sshd will skip the version-number exchange
161 */
Damien Miller95def091999-11-25 00:26:21 +1100162char *client_version_string = NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000163char *server_version_string = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000164
Ben Lindstrom8ac91062001-04-04 17:57:54 +0000165/* for rekeying XXX fixme */
166Kex *xxx_kex;
167
Damien Miller5428f641999-11-25 11:54:57 +1100168/*
169 * Any really sensitive data in the application is contained in this
170 * structure. The idea is that this structure could be locked into memory so
171 * that the pages do not get written into swap. However, there are some
172 * problems. The private key contains BIGNUMs, and we do not (in principle)
173 * have access to the internals of them, and locking just the structure is
174 * not very useful. Currently, memory locking is not implemented.
175 */
Damien Miller95def091999-11-25 00:26:21 +1100176struct {
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000177 Key *server_key; /* ephemeral server key */
Damien Miller0bc1bd82000-11-13 22:57:25 +1100178 Key *ssh1_host_key; /* ssh1 host key */
179 Key **host_keys; /* all private host keys */
180 int have_ssh1_key;
181 int have_ssh2_key;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000182 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000183} sensitive_data;
184
Damien Miller5428f641999-11-25 11:54:57 +1100185/*
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000186 * Flag indicating whether the RSA server key needs to be regenerated.
187 * Is set in the SIGALRM handler and cleared when the key is regenerated.
Damien Miller5428f641999-11-25 11:54:57 +1100188 */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000189static volatile sig_atomic_t key_do_regen = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000190
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000191/* This is set to true when a signal is received. */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000192static volatile sig_atomic_t received_sighup = 0;
193static volatile sig_atomic_t received_sigterm = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000194
Damien Millerb38eff82000-04-01 11:09:21 +1000195/* session identifier, used by RSA-auth */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000196u_char session_id[16];
Damien Millerb38eff82000-04-01 11:09:21 +1000197
Damien Millereba71ba2000-04-29 23:57:08 +1000198/* same for ssh2 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000199u_char *session_id2 = NULL;
Darren Tucker502d3842003-06-28 12:38:01 +1000200u_int session_id2_len = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000201
Damien Miller942da032000-08-18 13:59:06 +1000202/* record remote hostname or ip */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000203u_int utmp_len = MAXHOSTNAMELEN;
Damien Miller942da032000-08-18 13:59:06 +1000204
Ben Lindstromd84df982001-12-06 16:35:40 +0000205/* options.max_startup sized array of fd ints */
206int *startup_pipes = NULL;
207int startup_pipe; /* in child */
208
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000209/* variables used for privilege separation */
Damien Miller8e7fb332003-02-24 12:03:03 +1100210int use_privsep;
Darren Tuckera8be9e22004-02-06 16:40:27 +1100211struct monitor *pmonitor = NULL;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000212
Darren Tucker3e33cec2003-10-02 16:12:36 +1000213/* global authentication context */
214Authctxt *the_authctxt = NULL;
215
Darren Tucker09991742004-07-17 17:05:14 +1000216/* message to be displayed after login */
217Buffer loginmsg;
218
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000219/* Prototypes for various functions defined later in this file. */
Ben Lindstrombba81212001-06-25 05:01:22 +0000220void destroy_sensitive_data(void);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000221void demote_sensitive_data(void);
Damien Miller98c7ad62000-03-09 21:27:49 +1100222
Ben Lindstrombba81212001-06-25 05:01:22 +0000223static void do_ssh1_kex(void);
224static void do_ssh2_kex(void);
Damien Miller874d77b2000-10-14 16:23:11 +1100225
Damien Miller98c7ad62000-03-09 21:27:49 +1100226/*
Damien Miller34132e52000-01-14 15:45:46 +1100227 * Close all listening sockets
228 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000229static void
Damien Miller34132e52000-01-14 15:45:46 +1100230close_listen_socks(void)
231{
232 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000233
Damien Miller34132e52000-01-14 15:45:46 +1100234 for (i = 0; i < num_listen_socks; i++)
235 close(listen_socks[i]);
236 num_listen_socks = -1;
237}
238
Ben Lindstromd84df982001-12-06 16:35:40 +0000239static void
240close_startup_pipes(void)
241{
242 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000243
Ben Lindstromd84df982001-12-06 16:35:40 +0000244 if (startup_pipes)
245 for (i = 0; i < options.max_startups; i++)
246 if (startup_pipes[i] != -1)
247 close(startup_pipes[i]);
248}
249
Damien Miller34132e52000-01-14 15:45:46 +1100250/*
Damien Miller95def091999-11-25 00:26:21 +1100251 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
252 * the effect is to reread the configuration file (and to regenerate
253 * the server key).
254 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000255static void
Damien Miller95def091999-11-25 00:26:21 +1100256sighup_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000257{
Ben Lindstrom07958482001-12-06 16:19:01 +0000258 int save_errno = errno;
259
Damien Miller95def091999-11-25 00:26:21 +1100260 received_sighup = 1;
261 signal(SIGHUP, sighup_handler);
Ben Lindstrom07958482001-12-06 16:19:01 +0000262 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000263}
264
Damien Miller95def091999-11-25 00:26:21 +1100265/*
266 * Called from the main program after receiving SIGHUP.
267 * Restarts the server.
268 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000269static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000270sighup_restart(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000271{
Damien Miller996acd22003-04-09 20:59:48 +1000272 logit("Received SIGHUP; restarting.");
Damien Miller34132e52000-01-14 15:45:46 +1100273 close_listen_socks();
Ben Lindstromd84df982001-12-06 16:35:40 +0000274 close_startup_pipes();
Damien Miller95def091999-11-25 00:26:21 +1100275 execv(saved_argv[0], saved_argv);
Damien Miller996acd22003-04-09 20:59:48 +1000276 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
Ben Lindstrom822b6342002-06-23 21:38:49 +0000277 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100278 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000279}
280
Damien Miller95def091999-11-25 00:26:21 +1100281/*
282 * Generic signal handler for terminating signals in the master daemon.
Damien Miller95def091999-11-25 00:26:21 +1100283 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000284static void
Damien Miller95def091999-11-25 00:26:21 +1100285sigterm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000286{
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000287 received_sigterm = sig;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000288}
289
Damien Miller95def091999-11-25 00:26:21 +1100290/*
291 * SIGCHLD handler. This is called whenever a child dies. This will then
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000292 * reap any zombies left by exited children.
Damien Miller95def091999-11-25 00:26:21 +1100293 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000294static void
Damien Miller95def091999-11-25 00:26:21 +1100295main_sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000296{
Damien Miller95def091999-11-25 00:26:21 +1100297 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000298 pid_t pid;
Damien Miller95def091999-11-25 00:26:21 +1100299 int status;
Damien Miller431f66b1999-11-21 18:31:57 +1100300
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000301 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
302 (pid < 0 && errno == EINTR))
Damien Miller95def091999-11-25 00:26:21 +1100303 ;
Damien Miller431f66b1999-11-21 18:31:57 +1100304
Damien Miller95def091999-11-25 00:26:21 +1100305 signal(SIGCHLD, main_sigchld_handler);
306 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000307}
308
Damien Miller95def091999-11-25 00:26:21 +1100309/*
310 * Signal handler for the alarm after the login grace period has expired.
311 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000312static void
Damien Miller95def091999-11-25 00:26:21 +1100313grace_alarm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000314{
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000315 /* XXX no idea how fix this signal handler */
316
Darren Tuckera8be9e22004-02-06 16:40:27 +1100317 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
318 kill(pmonitor->m_pid, SIGALRM);
319
Damien Miller95def091999-11-25 00:26:21 +1100320 /* Log error and exit. */
Damien Millerd27a76d2002-09-27 13:22:31 +1000321 fatal("Timeout before authentication for %s", get_remote_ipaddr());
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000322}
323
Damien Miller95def091999-11-25 00:26:21 +1100324/*
Damien Miller95def091999-11-25 00:26:21 +1100325 * Signal handler for the key regeneration alarm. Note that this
326 * alarm only occurs in the daemon waiting for connections, and it does not
327 * do anything with the private key or random state before forking.
328 * Thus there should be no concurrency control/asynchronous execution
329 * problems.
330 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000331static void
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000332generate_ephemeral_server_key(void)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100333{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000334 u_int32_t rnd = 0;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000335 int i;
336
Ben Lindstroma3700052001-04-05 23:26:32 +0000337 verbose("Generating %s%d bit RSA key.",
Damien Millerff75ac42001-03-30 10:50:32 +1000338 sensitive_data.server_key ? "new " : "", options.server_key_bits);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100339 if (sensitive_data.server_key != NULL)
340 key_free(sensitive_data.server_key);
Ben Lindstroma3700052001-04-05 23:26:32 +0000341 sensitive_data.server_key = key_generate(KEY_RSA1,
Damien Millerff75ac42001-03-30 10:50:32 +1000342 options.server_key_bits);
343 verbose("RSA key generation complete.");
Ben Lindstromeb648a72001-03-05 06:00:29 +0000344
345 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
346 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000347 rnd = arc4random();
348 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
349 rnd >>= 8;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000350 }
351 arc4random_stir();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100352}
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000353
Ben Lindstrombba81212001-06-25 05:01:22 +0000354static void
Damien Miller95def091999-11-25 00:26:21 +1100355key_regeneration_alarm(int sig)
356{
357 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000358
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000359 signal(SIGALRM, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +1100360 errno = save_errno;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000361 key_do_regen = 1;
Damien Miller95def091999-11-25 00:26:21 +1100362}
363
Ben Lindstrombba81212001-06-25 05:01:22 +0000364static void
Damien Millerb38eff82000-04-01 11:09:21 +1000365sshd_exchange_identification(int sock_in, int sock_out)
366{
Damien Millereccb9de2005-06-17 12:59:34 +1000367 u_int i;
368 int mismatch;
Damien Millerb38eff82000-04-01 11:09:21 +1000369 int remote_major, remote_minor;
Damien Miller78928792000-04-12 20:17:38 +1000370 int major, minor;
Damien Millerb38eff82000-04-01 11:09:21 +1000371 char *s;
372 char buf[256]; /* Must not be larger than remote_version. */
373 char remote_version[256]; /* Must be at least as big as buf. */
374
Damien Miller78928792000-04-12 20:17:38 +1000375 if ((options.protocol & SSH_PROTO_1) &&
376 (options.protocol & SSH_PROTO_2)) {
377 major = PROTOCOL_MAJOR_1;
378 minor = 99;
379 } else if (options.protocol & SSH_PROTO_2) {
380 major = PROTOCOL_MAJOR_2;
381 minor = PROTOCOL_MINOR_2;
382 } else {
383 major = PROTOCOL_MAJOR_1;
384 minor = PROTOCOL_MINOR_1;
385 }
386 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
Damien Millerb38eff82000-04-01 11:09:21 +1000387 server_version_string = xstrdup(buf);
388
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000389 /* Send our protocol version identification. */
390 if (atomicio(vwrite, sock_out, server_version_string,
391 strlen(server_version_string))
392 != strlen(server_version_string)) {
393 logit("Could not write ident string to %s", get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000394 cleanup_exit(255);
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000395 }
396
397 /* Read other sides version identification. */
398 memset(buf, 0, sizeof(buf));
399 for (i = 0; i < sizeof(buf) - 1; i++) {
400 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
401 logit("Did not receive identification string from %s",
402 get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000403 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000404 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000405 if (buf[i] == '\r') {
406 buf[i] = 0;
407 /* Kludge for F-Secure Macintosh < 1.0.2 */
408 if (i == 12 &&
409 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
Damien Millerb38eff82000-04-01 11:09:21 +1000410 break;
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000411 continue;
Damien Millerb38eff82000-04-01 11:09:21 +1000412 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000413 if (buf[i] == '\n') {
414 buf[i] = 0;
415 break;
416 }
Damien Millerb38eff82000-04-01 11:09:21 +1000417 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000418 buf[sizeof(buf) - 1] = 0;
419 client_version_string = xstrdup(buf);
Damien Millerb38eff82000-04-01 11:09:21 +1000420
421 /*
422 * Check that the versions match. In future this might accept
423 * several versions and set appropriate flags to handle them.
424 */
425 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
426 &remote_major, &remote_minor, remote_version) != 3) {
Damien Miller4af51302000-04-16 11:18:38 +1000427 s = "Protocol mismatch.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000428 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Millerb38eff82000-04-01 11:09:21 +1000429 close(sock_in);
430 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000431 logit("Bad protocol version identification '%.100s' from %s",
Damien Millerb38eff82000-04-01 11:09:21 +1000432 client_version_string, get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000433 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000434 }
435 debug("Client protocol version %d.%d; client software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100436 remote_major, remote_minor, remote_version);
Damien Millerb38eff82000-04-01 11:09:21 +1000437
Damien Millerefb4afe2000-04-12 18:45:05 +1000438 compat_datafellows(remote_version);
439
Damien Millere9264972002-09-30 11:59:21 +1000440 if (datafellows & SSH_BUG_PROBE) {
Damien Miller996acd22003-04-09 20:59:48 +1000441 logit("probed from %s with %s. Don't panic.",
Damien Millere9264972002-09-30 11:59:21 +1000442 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000443 cleanup_exit(255);
Damien Millere9264972002-09-30 11:59:21 +1000444 }
445
Damien Miller27dbe6f2001-03-19 22:36:20 +1100446 if (datafellows & SSH_BUG_SCANNER) {
Damien Miller996acd22003-04-09 20:59:48 +1000447 logit("scanned from %s with %s. Don't panic.",
Damien Miller27dbe6f2001-03-19 22:36:20 +1100448 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000449 cleanup_exit(255);
Damien Miller27dbe6f2001-03-19 22:36:20 +1100450 }
451
Damien Miller78928792000-04-12 20:17:38 +1000452 mismatch = 0;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000453 switch (remote_major) {
Damien Millerb38eff82000-04-01 11:09:21 +1000454 case 1:
Damien Millereba71ba2000-04-29 23:57:08 +1000455 if (remote_minor == 99) {
456 if (options.protocol & SSH_PROTO_2)
457 enable_compat20();
458 else
459 mismatch = 1;
460 break;
461 }
Damien Miller78928792000-04-12 20:17:38 +1000462 if (!(options.protocol & SSH_PROTO_1)) {
463 mismatch = 1;
464 break;
465 }
Damien Millerb38eff82000-04-01 11:09:21 +1000466 if (remote_minor < 3) {
Damien Miller37023962000-07-11 17:31:38 +1000467 packet_disconnect("Your ssh version is too old and "
Damien Millerb38eff82000-04-01 11:09:21 +1000468 "is no longer supported. Please install a newer version.");
469 } else if (remote_minor == 3) {
470 /* note that this disables agent-forwarding */
471 enable_compat13();
472 }
Damien Miller78928792000-04-12 20:17:38 +1000473 break;
Damien Millerefb4afe2000-04-12 18:45:05 +1000474 case 2:
Damien Miller78928792000-04-12 20:17:38 +1000475 if (options.protocol & SSH_PROTO_2) {
Damien Millerefb4afe2000-04-12 18:45:05 +1000476 enable_compat20();
477 break;
478 }
479 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000480 default:
Damien Miller78928792000-04-12 20:17:38 +1000481 mismatch = 1;
Damien Millerb38eff82000-04-01 11:09:21 +1000482 break;
483 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000484 chop(server_version_string);
Damien Miller78928792000-04-12 20:17:38 +1000485 debug("Local version string %.200s", server_version_string);
486
487 if (mismatch) {
488 s = "Protocol major versions differ.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000489 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Miller78928792000-04-12 20:17:38 +1000490 close(sock_in);
491 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000492 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
Damien Miller78928792000-04-12 20:17:38 +1000493 get_remote_ipaddr(),
494 server_version_string, client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000495 cleanup_exit(255);
Damien Miller78928792000-04-12 20:17:38 +1000496 }
Damien Millereba71ba2000-04-29 23:57:08 +1000497}
498
Damien Miller0bc1bd82000-11-13 22:57:25 +1100499/* Destroy the host and server keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +1000500void
501destroy_sensitive_data(void)
502{
Damien Miller0bc1bd82000-11-13 22:57:25 +1100503 int i;
504
505 if (sensitive_data.server_key) {
506 key_free(sensitive_data.server_key);
507 sensitive_data.server_key = NULL;
508 }
Damien Miller9f0f5c62001-12-21 14:45:46 +1100509 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100510 if (sensitive_data.host_keys[i]) {
511 key_free(sensitive_data.host_keys[i]);
512 sensitive_data.host_keys[i] = NULL;
513 }
514 }
515 sensitive_data.ssh1_host_key = NULL;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000516 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100517}
Damien Miller0bc1bd82000-11-13 22:57:25 +1100518
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000519/* Demote private to public keys for network child */
520void
521demote_sensitive_data(void)
522{
523 Key *tmp;
524 int i;
525
526 if (sensitive_data.server_key) {
527 tmp = key_demote(sensitive_data.server_key);
528 key_free(sensitive_data.server_key);
529 sensitive_data.server_key = tmp;
530 }
531
532 for (i = 0; i < options.num_host_key_files; i++) {
533 if (sensitive_data.host_keys[i]) {
534 tmp = key_demote(sensitive_data.host_keys[i]);
535 key_free(sensitive_data.host_keys[i]);
536 sensitive_data.host_keys[i] = tmp;
537 if (tmp->type == KEY_RSA1)
538 sensitive_data.ssh1_host_key = tmp;
539 }
540 }
541
542 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
543}
544
Ben Lindstrom08105192002-03-22 02:50:06 +0000545static void
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000546privsep_preauth_child(void)
547{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000548 u_int32_t rnd[256];
Ben Lindstrom810af962002-07-04 00:11:40 +0000549 gid_t gidset[1];
Ben Lindstromc7431342002-03-22 03:11:49 +0000550 struct passwd *pw;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000551 int i;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000552
553 /* Enable challenge-response authentication for privilege separation */
554 privsep_challenge_enable();
555
556 for (i = 0; i < 256; i++)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000557 rnd[i] = arc4random();
558 RAND_seed(rnd, sizeof(rnd));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000559
560 /* Demote the private keys to public keys. */
561 demote_sensitive_data();
562
Ben Lindstromc7431342002-03-22 03:11:49 +0000563 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
Damien Miller0150c652002-04-24 09:49:09 +1000564 fatal("Privilege separation user %s does not exist",
565 SSH_PRIVSEP_USER);
Ben Lindstromc7431342002-03-22 03:11:49 +0000566 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
567 endpwent();
568
Ben Lindstroma962c2f2002-07-04 00:14:17 +0000569 /* Change our root directory */
Ben Lindstrom7a7edf72002-03-22 02:42:37 +0000570 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
571 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
572 strerror(errno));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000573 if (chdir("/") == -1)
Ben Lindstrom1ee9ec32002-03-22 03:14:45 +0000574 fatal("chdir(\"/\"): %s", strerror(errno));
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000575
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000576 /* Drop our privileges */
Ben Lindstromc7431342002-03-22 03:11:49 +0000577 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
578 (u_int)pw->pw_gid);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000579#if 0
Darren Tuckerd5920482004-02-29 20:11:30 +1100580 /* XXX not ready, too heavy after chroot */
Ben Lindstromc7431342002-03-22 03:11:49 +0000581 do_setusercontext(pw);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000582#else
583 gidset[0] = pw->pw_gid;
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000584 if (setgroups(1, gidset) < 0)
585 fatal("setgroups: %.100s", strerror(errno));
586 permanently_set_uid(pw);
587#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000588}
589
Darren Tucker3e33cec2003-10-02 16:12:36 +1000590static int
591privsep_preauth(Authctxt *authctxt)
Ben Lindstrom943481c2002-03-22 03:43:46 +0000592{
Ben Lindstrom943481c2002-03-22 03:43:46 +0000593 int status;
594 pid_t pid;
595
596 /* Set up unprivileged child process to deal with network data */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000597 pmonitor = monitor_init();
Ben Lindstrom943481c2002-03-22 03:43:46 +0000598 /* Store a pointer to the kex for later rekeying */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000599 pmonitor->m_pkex = &xxx_kex;
Ben Lindstrom943481c2002-03-22 03:43:46 +0000600
601 pid = fork();
602 if (pid == -1) {
603 fatal("fork of unprivileged child failed");
604 } else if (pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000605 debug2("Network child is on pid %ld", (long)pid);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000606
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000607 close(pmonitor->m_recvfd);
Darren Tuckera8be9e22004-02-06 16:40:27 +1100608 pmonitor->m_pid = pid;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000609 monitor_child_preauth(authctxt, pmonitor);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000610 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000611
612 /* Sync memory */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000613 monitor_sync(pmonitor);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000614
615 /* Wait for the child's exit status */
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000616 while (waitpid(pid, &status, 0) < 0)
617 if (errno != EINTR)
618 break;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000619 return (1);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000620 } else {
621 /* child */
622
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000623 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000624
625 /* Demote the child */
626 if (getuid() == 0 || geteuid() == 0)
627 privsep_preauth_child();
Ben Lindstromf90f58d2002-03-26 01:53:03 +0000628 setproctitle("%s", "[net]");
Ben Lindstrom943481c2002-03-22 03:43:46 +0000629 }
Darren Tucker3e33cec2003-10-02 16:12:36 +1000630 return (0);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000631}
632
Ben Lindstrom08105192002-03-22 02:50:06 +0000633static void
Ben Lindstrom943481c2002-03-22 03:43:46 +0000634privsep_postauth(Authctxt *authctxt)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000635{
Tim Rice9dd30812002-07-07 13:43:36 -0700636#ifdef DISABLE_FD_PASSING
Tim Rice8eff3192002-06-25 15:35:15 -0700637 if (1) {
638#else
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000639 if (authctxt->pw->pw_uid == 0 || options.use_login) {
Tim Rice8eff3192002-06-25 15:35:15 -0700640#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000641 /* File descriptor passing is broken or root login */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000642 use_privsep = 0;
Darren Tucker45b01422005-10-03 18:20:00 +1000643 goto skip;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000644 }
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000645
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000646 /* New socket pair */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000647 monitor_reinit(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000648
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000649 pmonitor->m_pid = fork();
650 if (pmonitor->m_pid == -1)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000651 fatal("fork of unprivileged child failed");
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000652 else if (pmonitor->m_pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000653 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000654 close(pmonitor->m_recvfd);
Darren Tuckereb578622004-08-12 23:08:14 +1000655 buffer_clear(&loginmsg);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000656 monitor_child_postauth(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000657
658 /* NEVERREACHED */
659 exit(0);
660 }
661
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000662 close(pmonitor->m_sendfd);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000663
664 /* Demote the private keys to public keys. */
665 demote_sensitive_data();
666
667 /* Drop privileges */
668 do_setusercontext(authctxt->pw);
669
Darren Tucker45b01422005-10-03 18:20:00 +1000670 skip:
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000671 /* It is safe now to apply the key state */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000672 monitor_apply_keystate(pmonitor);
Damien Miller9786e6e2005-07-26 21:54:56 +1000673
674 /*
675 * Tell the packet layer that authentication was successful, since
676 * this information is not part of the key state.
677 */
678 packet_set_authenticated();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000679}
680
Ben Lindstrombba81212001-06-25 05:01:22 +0000681static char *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100682list_hostkey_types(void)
683{
Damien Miller0e3b8722002-01-22 23:26:38 +1100684 Buffer b;
Damien Millerf58b58c2003-11-17 21:18:23 +1100685 const char *p;
686 char *ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100687 int i;
Damien Miller0e3b8722002-01-22 23:26:38 +1100688
689 buffer_init(&b);
Damien Miller9f0f5c62001-12-21 14:45:46 +1100690 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100691 Key *key = sensitive_data.host_keys[i];
692 if (key == NULL)
693 continue;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000694 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100695 case KEY_RSA:
696 case KEY_DSA:
Damien Miller0e3b8722002-01-22 23:26:38 +1100697 if (buffer_len(&b) > 0)
698 buffer_append(&b, ",", 1);
699 p = key_ssh_name(key);
700 buffer_append(&b, p, strlen(p));
Damien Miller0bc1bd82000-11-13 22:57:25 +1100701 break;
702 }
703 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100704 buffer_append(&b, "\0", 1);
Damien Millerf58b58c2003-11-17 21:18:23 +1100705 ret = xstrdup(buffer_ptr(&b));
Damien Miller0e3b8722002-01-22 23:26:38 +1100706 buffer_free(&b);
Damien Millerf58b58c2003-11-17 21:18:23 +1100707 debug("list_hostkey_types: %s", ret);
708 return ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100709}
710
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000711Key *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100712get_hostkey_by_type(int type)
713{
714 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000715
Damien Miller9f0f5c62001-12-21 14:45:46 +1100716 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100717 Key *key = sensitive_data.host_keys[i];
718 if (key != NULL && key->type == type)
719 return key;
720 }
721 return NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000722}
723
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000724Key *
725get_hostkey_by_index(int ind)
726{
727 if (ind < 0 || ind >= options.num_host_key_files)
728 return (NULL);
729 return (sensitive_data.host_keys[ind]);
730}
731
732int
733get_hostkey_index(Key *key)
734{
735 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000736
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000737 for (i = 0; i < options.num_host_key_files; i++) {
738 if (key == sensitive_data.host_keys[i])
739 return (i);
740 }
741 return (-1);
742}
743
Damien Miller942da032000-08-18 13:59:06 +1000744/*
745 * returns 1 if connection should be dropped, 0 otherwise.
746 * dropping starts at connection #max_startups_begin with a probability
747 * of (max_startups_rate/100). the probability increases linearly until
748 * all connections are dropped for startups > max_startups
749 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000750static int
Damien Miller942da032000-08-18 13:59:06 +1000751drop_connection(int startups)
752{
Darren Tucker178fa662004-11-05 20:09:09 +1100753 int p, r;
Damien Miller942da032000-08-18 13:59:06 +1000754
755 if (startups < options.max_startups_begin)
756 return 0;
757 if (startups >= options.max_startups)
758 return 1;
759 if (options.max_startups_rate == 100)
760 return 1;
761
762 p = 100 - options.max_startups_rate;
763 p *= startups - options.max_startups_begin;
Darren Tucker178fa662004-11-05 20:09:09 +1100764 p /= options.max_startups - options.max_startups_begin;
Damien Miller942da032000-08-18 13:59:06 +1000765 p += options.max_startups_rate;
Darren Tucker178fa662004-11-05 20:09:09 +1100766 r = arc4random() % 100;
Damien Miller942da032000-08-18 13:59:06 +1000767
Darren Tucker3269b132004-11-05 20:20:59 +1100768 debug("drop_connection: p %d, r %d", p, r);
Damien Miller942da032000-08-18 13:59:06 +1000769 return (r < p) ? 1 : 0;
770}
771
Ben Lindstromade03f62001-12-06 18:22:17 +0000772static void
773usage(void)
774{
Damien Miller0c889cd2004-03-22 09:36:00 +1100775 fprintf(stderr, "%s, %s\n",
Damien Miller2aa6d3c2004-09-12 16:53:04 +1000776 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
Damien Millerb4087862004-03-22 09:35:21 +1100777 fprintf(stderr,
778"usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n"
779" [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n"
780 );
Ben Lindstromade03f62001-12-06 18:22:17 +0000781 exit(1);
782}
783
Darren Tucker645ab752004-06-25 13:33:20 +1000784static void
785send_rexec_state(int fd, Buffer *conf)
786{
787 Buffer m;
788
789 debug3("%s: entering fd = %d config len %d", __func__, fd,
790 buffer_len(conf));
791
792 /*
793 * Protocol from reexec master to child:
794 * string configuration
795 * u_int ephemeral_key_follows
796 * bignum e (only if ephemeral_key_follows == 1)
797 * bignum n "
798 * bignum d "
799 * bignum iqmp "
800 * bignum p "
801 * bignum q "
Darren Tuckerc6f82192005-09-27 22:46:32 +1000802 * string rngseed (only if OpenSSL is not self-seeded)
Darren Tucker645ab752004-06-25 13:33:20 +1000803 */
804 buffer_init(&m);
805 buffer_put_cstring(&m, buffer_ptr(conf));
806
Darren Tuckerfc959702004-07-17 16:12:08 +1000807 if (sensitive_data.server_key != NULL &&
Darren Tucker645ab752004-06-25 13:33:20 +1000808 sensitive_data.server_key->type == KEY_RSA1) {
809 buffer_put_int(&m, 1);
810 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
811 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
812 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
813 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
814 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
815 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
816 } else
817 buffer_put_int(&m, 0);
818
Darren Tuckerc6f82192005-09-27 22:46:32 +1000819#ifndef OPENSSL_PRNG_ONLY
820 rexec_send_rng_seed(&m);
821#endif
822
Darren Tucker645ab752004-06-25 13:33:20 +1000823 if (ssh_msg_send(fd, 0, &m) == -1)
824 fatal("%s: ssh_msg_send failed", __func__);
825
826 buffer_free(&m);
827
828 debug3("%s: done", __func__);
829}
830
831static void
832recv_rexec_state(int fd, Buffer *conf)
833{
834 Buffer m;
835 char *cp;
836 u_int len;
837
838 debug3("%s: entering fd = %d", __func__, fd);
839
840 buffer_init(&m);
841
842 if (ssh_msg_recv(fd, &m) == -1)
843 fatal("%s: ssh_msg_recv failed", __func__);
844 if (buffer_get_char(&m) != 0)
845 fatal("%s: rexec version mismatch", __func__);
846
847 cp = buffer_get_string(&m, &len);
848 if (conf != NULL)
849 buffer_append(conf, cp, len + 1);
850 xfree(cp);
851
852 if (buffer_get_int(&m)) {
853 if (sensitive_data.server_key != NULL)
854 key_free(sensitive_data.server_key);
855 sensitive_data.server_key = key_new_private(KEY_RSA1);
856 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
857 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
858 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
859 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
860 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
861 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
862 rsa_generate_additional_parameters(
863 sensitive_data.server_key->rsa);
864 }
Darren Tuckerc6f82192005-09-27 22:46:32 +1000865
866#ifndef OPENSSL_PRNG_ONLY
867 rexec_recv_rng_seed(&m);
868#endif
869
Darren Tucker645ab752004-06-25 13:33:20 +1000870 buffer_free(&m);
871
872 debug3("%s: done", __func__);
873}
874
Damien Miller95def091999-11-25 00:26:21 +1100875/*
876 * Main program for the daemon.
877 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000878int
879main(int ac, char **av)
880{
Damien Miller95def091999-11-25 00:26:21 +1100881 extern char *optarg;
882 extern int optind;
Damien Miller386c6a22004-06-30 22:40:20 +1000883 int opt, j, i, fdsetsz, on = 1;
884 int sock_in = -1, sock_out = -1, newsock = -1;
Damien Miller166fca82000-04-20 07:42:21 +1000885 pid_t pid;
Damien Miller34132e52000-01-14 15:45:46 +1100886 socklen_t fromlen;
Damien Miller34132e52000-01-14 15:45:46 +1100887 fd_set *fdset;
888 struct sockaddr_storage from;
Damien Miller95def091999-11-25 00:26:21 +1100889 const char *remote_ip;
890 int remote_port;
Damien Miller95def091999-11-25 00:26:21 +1100891 FILE *f;
Damien Miller34132e52000-01-14 15:45:46 +1100892 struct addrinfo *ai;
893 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
Damien Millerb9997192003-12-17 16:29:22 +1100894 char *line;
Damien Miller34132e52000-01-14 15:45:46 +1100895 int listen_sock, maxfd;
Darren Tucker0f56ed12004-08-29 16:38:41 +1000896 int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 };
Damien Miller37023962000-07-11 17:31:38 +1000897 int startups = 0;
Ben Lindstromd0fca422001-03-26 13:44:06 +0000898 Key *key;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000899 Authctxt *authctxt;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000900 int ret, key_used = 0;
Darren Tucker645ab752004-06-25 13:33:20 +1000901 Buffer cfg;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000902
Kevin Steves0ea1d9d2002-04-25 18:17:04 +0000903#ifdef HAVE_SECUREWARE
904 (void)set_auth_parameters(ac, av);
905#endif
Damien Miller59d3d5b2003-08-22 09:34:41 +1000906 __progname = ssh_get_progname(av[0]);
Damien Millerf9b625c2000-07-09 22:42:32 +1000907 init_rng();
908
Damien Millera8ed44b2003-01-10 09:53:12 +1100909 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
Damien Millerb8c656e2000-06-28 15:22:41 +1000910 saved_argc = ac;
Darren Tucker17c5d032004-06-25 14:22:23 +1000911 rexec_argc = ac;
Damien Miller04cb5362003-05-15 21:29:10 +1000912 saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1));
Damien Millera8ed44b2003-01-10 09:53:12 +1100913 for (i = 0; i < ac; i++)
914 saved_argv[i] = xstrdup(av[i]);
Damien Miller04cb5362003-05-15 21:29:10 +1000915 saved_argv[i] = NULL;
Damien Millera8ed44b2003-01-10 09:53:12 +1100916
917#ifndef HAVE_SETPROCTITLE
918 /* Prepare for later setproctitle emulation */
919 compat_init_setproctitle(ac, av);
Damien Millerf2e3e9d2003-06-02 12:15:54 +1000920 av = saved_argv;
Damien Millera8ed44b2003-01-10 09:53:12 +1100921#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000922
Damien Millerbfba3542004-03-22 09:29:57 +1100923 if (geteuid() == 0 && setgroups(0, NULL) == -1)
924 debug("setgroups(): %.200s", strerror(errno));
925
Darren Tuckerce321d82005-10-03 18:11:24 +1000926 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
927 sanitise_stdfd();
928
Damien Miller95def091999-11-25 00:26:21 +1100929 /* Initialize configuration options to their default values. */
930 initialize_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000931
Damien Miller95def091999-11-25 00:26:21 +1100932 /* Parse command-line arguments. */
Darren Tucker645ab752004-06-25 13:33:20 +1000933 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) {
Damien Miller95def091999-11-25 00:26:21 +1100934 switch (opt) {
Damien Miller34132e52000-01-14 15:45:46 +1100935 case '4':
Darren Tucker0f383232005-01-20 10:57:56 +1100936 options.address_family = AF_INET;
Damien Miller34132e52000-01-14 15:45:46 +1100937 break;
938 case '6':
Darren Tucker0f383232005-01-20 10:57:56 +1100939 options.address_family = AF_INET6;
Damien Miller34132e52000-01-14 15:45:46 +1100940 break;
Damien Miller95def091999-11-25 00:26:21 +1100941 case 'f':
942 config_file_name = optarg;
943 break;
944 case 'd':
Darren Tuckere98dfa32003-07-19 19:54:31 +1000945 if (debug_flag == 0) {
Damien Millere4340be2000-09-16 13:29:08 +1100946 debug_flag = 1;
947 options.log_level = SYSLOG_LEVEL_DEBUG1;
Darren Tuckere98dfa32003-07-19 19:54:31 +1000948 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
Damien Millere4340be2000-09-16 13:29:08 +1100949 options.log_level++;
Damien Miller95def091999-11-25 00:26:21 +1100950 break;
Ben Lindstromc72745a2000-12-02 19:03:54 +0000951 case 'D':
952 no_daemon_flag = 1;
953 break;
Ben Lindstrom9fce9f02001-04-11 23:10:09 +0000954 case 'e':
955 log_stderr = 1;
956 break;
Damien Miller95def091999-11-25 00:26:21 +1100957 case 'i':
958 inetd_flag = 1;
959 break;
Darren Tucker645ab752004-06-25 13:33:20 +1000960 case 'r':
961 rexec_flag = 0;
962 break;
963 case 'R':
964 rexeced_flag = 1;
965 inetd_flag = 1;
966 break;
Damien Miller95def091999-11-25 00:26:21 +1100967 case 'Q':
Ben Lindstromd5390202001-01-29 08:07:43 +0000968 /* ignored */
Damien Miller95def091999-11-25 00:26:21 +1100969 break;
970 case 'q':
971 options.log_level = SYSLOG_LEVEL_QUIET;
972 break;
973 case 'b':
974 options.server_key_bits = atoi(optarg);
975 break;
976 case 'p':
Damien Miller34132e52000-01-14 15:45:46 +1100977 options.ports_from_cmdline = 1;
Damien Millere4340be2000-09-16 13:29:08 +1100978 if (options.num_ports >= MAX_PORTS) {
979 fprintf(stderr, "too many ports.\n");
980 exit(1);
981 }
Ben Lindstrom19066a12001-04-12 23:39:26 +0000982 options.ports[options.num_ports++] = a2port(optarg);
983 if (options.ports[options.num_ports-1] == 0) {
984 fprintf(stderr, "Bad port number.\n");
985 exit(1);
986 }
Damien Miller95def091999-11-25 00:26:21 +1100987 break;
988 case 'g':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +0000989 if ((options.login_grace_time = convtime(optarg)) == -1) {
990 fprintf(stderr, "Invalid login grace time.\n");
991 exit(1);
992 }
Damien Miller95def091999-11-25 00:26:21 +1100993 break;
994 case 'k':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +0000995 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
996 fprintf(stderr, "Invalid key regeneration interval.\n");
997 exit(1);
998 }
Damien Miller95def091999-11-25 00:26:21 +1100999 break;
1000 case 'h':
Damien Miller0bc1bd82000-11-13 22:57:25 +11001001 if (options.num_host_key_files >= MAX_HOSTKEYS) {
1002 fprintf(stderr, "too many host keys.\n");
1003 exit(1);
1004 }
1005 options.host_key_files[options.num_host_key_files++] = optarg;
Damien Miller95def091999-11-25 00:26:21 +11001006 break;
Ben Lindstrom794325a2001-08-06 21:09:07 +00001007 case 't':
1008 test_flag = 1;
1009 break;
Damien Miller942da032000-08-18 13:59:06 +10001010 case 'u':
1011 utmp_len = atoi(optarg);
Ben Lindstrom41daec72002-07-23 21:15:13 +00001012 if (utmp_len > MAXHOSTNAMELEN) {
1013 fprintf(stderr, "Invalid utmp length.\n");
1014 exit(1);
1015 }
Damien Miller942da032000-08-18 13:59:06 +10001016 break;
Ben Lindstromade03f62001-12-06 18:22:17 +00001017 case 'o':
Damien Millerb9997192003-12-17 16:29:22 +11001018 line = xstrdup(optarg);
1019 if (process_server_config_line(&options, line,
Ben Lindstromade03f62001-12-06 18:22:17 +00001020 "command-line", 0) != 0)
Damien Miller9f0f5c62001-12-21 14:45:46 +11001021 exit(1);
Damien Millerb9997192003-12-17 16:29:22 +11001022 xfree(line);
Ben Lindstromade03f62001-12-06 18:22:17 +00001023 break;
Damien Miller95def091999-11-25 00:26:21 +11001024 case '?':
1025 default:
Ben Lindstromade03f62001-12-06 18:22:17 +00001026 usage();
1027 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001028 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001029 }
Darren Tucker645ab752004-06-25 13:33:20 +10001030 if (rexeced_flag || inetd_flag)
1031 rexec_flag = 0;
1032 if (rexec_flag && (av[0] == NULL || *av[0] != '/'))
1033 fatal("sshd re-exec requires execution with an absolute path");
1034 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001035 closefrom(REEXEC_MIN_FREE_FD);
1036 else
1037 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001038
Ben Lindstrom425fb022001-03-29 00:31:20 +00001039 SSLeay_add_all_algorithms();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001040
Damien Miller34132e52000-01-14 15:45:46 +11001041 /*
1042 * Force logging to stderr until we have loaded the private host
1043 * key (unless started from inetd)
1044 */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001045 log_init(__progname,
Damien Miller5aa5d782002-02-08 22:01:54 +11001046 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1047 SYSLOG_LEVEL_INFO : options.log_level,
1048 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1049 SYSLOG_FACILITY_AUTH : options.log_facility,
Ben Lindstromc2faa4a2002-11-09 15:50:03 +00001050 log_stderr || !inetd_flag);
Damien Miller34132e52000-01-14 15:45:46 +11001051
Darren Tucker86c093d2004-03-08 22:59:03 +11001052 /*
1053 * Unset KRB5CCNAME, otherwise the user's session may inherit it from
1054 * root's environment
Damien Miller94cf4c82005-07-17 17:04:47 +10001055 */
Darren Tucker9dc6c7d2005-02-02 18:30:33 +11001056 if (getenv("KRB5CCNAME") != NULL)
1057 unsetenv("KRB5CCNAME");
1058
Tim Rice81ed5182002-09-25 17:38:46 -07001059#ifdef _UNICOS
Darren Tucker12984962004-05-24 13:37:13 +10001060 /* Cray can define user privs drop all privs now!
Ben Lindstrom6db66ff2001-08-06 23:29:16 +00001061 * Not needed on PRIV_SU systems!
1062 */
1063 drop_cray_privs();
1064#endif
1065
Darren Tucker645ab752004-06-25 13:33:20 +10001066 sensitive_data.server_key = NULL;
1067 sensitive_data.ssh1_host_key = NULL;
1068 sensitive_data.have_ssh1_key = 0;
1069 sensitive_data.have_ssh2_key = 0;
1070
1071 /* Fetch our configuration */
1072 buffer_init(&cfg);
1073 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001074 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
Darren Tucker645ab752004-06-25 13:33:20 +10001075 else
1076 load_server_config(config_file_name, &cfg);
1077
1078 parse_server_config(&options,
1079 rexeced_flag ? "rexec" : config_file_name, &cfg);
1080
1081 if (!rexec_flag)
1082 buffer_free(&cfg);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001083
Darren Tuckerc6f82192005-09-27 22:46:32 +10001084 seed_rng();
1085
Damien Miller95def091999-11-25 00:26:21 +11001086 /* Fill in default values for those options not explicitly set. */
1087 fill_default_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001088
Darren Tucker0f383232005-01-20 10:57:56 +11001089 /* set default channel AF */
1090 channel_set_af(options.address_family);
1091
Damien Miller95def091999-11-25 00:26:21 +11001092 /* Check that there are no remaining arguments. */
1093 if (optind < ac) {
1094 fprintf(stderr, "Extra argument %s.\n", av[optind]);
1095 exit(1);
1096 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001097
Damien Miller2aa6d3c2004-09-12 16:53:04 +10001098 debug("sshd version %.100s", SSH_RELEASE);
Damien Miller2ccf6611999-11-15 15:25:10 +11001099
Damien Miller0bc1bd82000-11-13 22:57:25 +11001100 /* load private host keys */
Ben Lindstroma962c2f2002-07-04 00:14:17 +00001101 sensitive_data.host_keys = xmalloc(options.num_host_key_files *
1102 sizeof(Key *));
Damien Miller9f0f5c62001-12-21 14:45:46 +11001103 for (i = 0; i < options.num_host_key_files; i++)
Ben Lindstrom46c16222000-12-22 01:43:59 +00001104 sensitive_data.host_keys[i] = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +10001105
Damien Miller9f0f5c62001-12-21 14:45:46 +11001106 for (i = 0; i < options.num_host_key_files; i++) {
Ben Lindstromd0fca422001-03-26 13:44:06 +00001107 key = key_load_private(options.host_key_files[i], "", NULL);
1108 sensitive_data.host_keys[i] = key;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001109 if (key == NULL) {
Ben Lindstrom15f33862001-04-16 02:00:02 +00001110 error("Could not load host key: %s",
1111 options.host_key_files[i]);
Ben Lindstromd0fca422001-03-26 13:44:06 +00001112 sensitive_data.host_keys[i] = NULL;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001113 continue;
1114 }
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +00001115 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +11001116 case KEY_RSA1:
1117 sensitive_data.ssh1_host_key = key;
1118 sensitive_data.have_ssh1_key = 1;
1119 break;
1120 case KEY_RSA:
1121 case KEY_DSA:
1122 sensitive_data.have_ssh2_key = 1;
1123 break;
1124 }
Ben Lindstromd0fca422001-03-26 13:44:06 +00001125 debug("private host key: #%d type %d %s", i, key->type,
1126 key_type(key));
Damien Miller0bc1bd82000-11-13 22:57:25 +11001127 }
1128 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001129 logit("Disabling protocol version 1. Could not load host key");
Damien Millereba71ba2000-04-29 23:57:08 +10001130 options.protocol &= ~SSH_PROTO_1;
1131 }
Damien Miller0bc1bd82000-11-13 22:57:25 +11001132 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001133 logit("Disabling protocol version 2. Could not load host key");
Damien Miller0bc1bd82000-11-13 22:57:25 +11001134 options.protocol &= ~SSH_PROTO_2;
Damien Millereba71ba2000-04-29 23:57:08 +10001135 }
Kevin Stevesadf74cd2001-02-05 14:22:50 +00001136 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
Damien Miller996acd22003-04-09 20:59:48 +10001137 logit("sshd: no hostkeys available -- exiting.");
Damien Miller95def091999-11-25 00:26:21 +11001138 exit(1);
1139 }
Damien Miller95def091999-11-25 00:26:21 +11001140
Damien Millereba71ba2000-04-29 23:57:08 +10001141 /* Check certain values for sanity. */
1142 if (options.protocol & SSH_PROTO_1) {
1143 if (options.server_key_bits < 512 ||
1144 options.server_key_bits > 32768) {
1145 fprintf(stderr, "Bad server key size.\n");
1146 exit(1);
1147 }
1148 /*
1149 * Check that server and host key lengths differ sufficiently. This
1150 * is necessary to make double encryption work with rsaref. Oh, I
1151 * hate software patents. I dont know if this can go? Niels
1152 */
1153 if (options.server_key_bits >
Ben Lindstrom822b6342002-06-23 21:38:49 +00001154 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1155 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1156 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1157 SSH_KEY_BITS_RESERVED) {
Damien Millereba71ba2000-04-29 23:57:08 +10001158 options.server_key_bits =
Ben Lindstrom822b6342002-06-23 21:38:49 +00001159 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1160 SSH_KEY_BITS_RESERVED;
Damien Millereba71ba2000-04-29 23:57:08 +10001161 debug("Forcing server key to %d bits to make it differ from host key.",
1162 options.server_key_bits);
1163 }
1164 }
1165
Ben Lindstroma26ea632002-06-06 20:46:25 +00001166 if (use_privsep) {
1167 struct passwd *pw;
1168 struct stat st;
1169
1170 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1171 fatal("Privilege separation user %s does not exist",
1172 SSH_PRIVSEP_USER);
1173 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1174 (S_ISDIR(st.st_mode) == 0))
1175 fatal("Missing privilege separation directory: %s",
1176 _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstrom59627352002-06-27 18:02:21 +00001177
1178#ifdef HAVE_CYGWIN
1179 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1180 (st.st_uid != getuid () ||
1181 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1182#else
Ben Lindstrom2dfacb32002-06-23 00:33:47 +00001183 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
Ben Lindstrom59627352002-06-27 18:02:21 +00001184#endif
Damien Miller180fc5b2003-02-24 11:50:18 +11001185 fatal("%s must be owned by root and not group or "
1186 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstroma26ea632002-06-06 20:46:25 +00001187 }
1188
Ben Lindstrom794325a2001-08-06 21:09:07 +00001189 /* Configuration looks good, so exit if in test mode. */
1190 if (test_flag)
1191 exit(0);
1192
Damien Miller87aea252002-05-10 12:20:24 +10001193 /*
1194 * Clear out any supplemental groups we may have inherited. This
1195 * prevents inadvertent creation of files with bad modes (in the
Damien Millera8e06ce2003-11-21 23:48:55 +11001196 * portable version at least, it's certainly possible for PAM
1197 * to create a file, and we can't control the code in every
Damien Miller87aea252002-05-10 12:20:24 +10001198 * module which might be used).
1199 */
1200 if (setgroups(0, NULL) < 0)
1201 debug("setgroups() failed: %.200s", strerror(errno));
1202
Darren Tucker645ab752004-06-25 13:33:20 +10001203 if (rexec_flag) {
1204 rexec_argv = xmalloc(sizeof(char *) * (rexec_argc + 2));
1205 for (i = 0; i < rexec_argc; i++) {
1206 debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1207 rexec_argv[i] = saved_argv[i];
1208 }
1209 rexec_argv[rexec_argc] = "-R";
1210 rexec_argv[rexec_argc + 1] = NULL;
1211 }
1212
Damien Millereba71ba2000-04-29 23:57:08 +10001213 /* Initialize the log (it is reinitialized below in case we forked). */
Darren Tuckerea7c8122005-01-20 11:03:08 +11001214 if (debug_flag && (!inetd_flag || rexeced_flag))
Damien Miller95def091999-11-25 00:26:21 +11001215 log_stderr = 1;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001216 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001217
Damien Millereba71ba2000-04-29 23:57:08 +10001218 /*
1219 * If not in debugging mode, and not started from inetd, disconnect
1220 * from the controlling terminal, and fork. The original process
1221 * exits.
1222 */
Ben Lindstromc72745a2000-12-02 19:03:54 +00001223 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
Damien Miller95def091999-11-25 00:26:21 +11001224#ifdef TIOCNOTTY
1225 int fd;
1226#endif /* TIOCNOTTY */
1227 if (daemon(0, 0) < 0)
1228 fatal("daemon() failed: %.200s", strerror(errno));
1229
1230 /* Disconnect from the controlling tty. */
1231#ifdef TIOCNOTTY
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001232 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +11001233 if (fd >= 0) {
1234 (void) ioctl(fd, TIOCNOTTY, NULL);
1235 close(fd);
1236 }
1237#endif /* TIOCNOTTY */
1238 }
1239 /* Reinitialize the log (because of the fork above). */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001240 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001241
Damien Miller95def091999-11-25 00:26:21 +11001242 /* Initialize the random number generator. */
1243 arc4random_stir();
1244
1245 /* Chdir to the root directory so that the current disk can be
1246 unmounted if desired. */
1247 chdir("/");
Damien Miller9f0f5c62001-12-21 14:45:46 +11001248
Ben Lindstromde71cda2001-03-24 00:43:26 +00001249 /* ignore SIGPIPE */
1250 signal(SIGPIPE, SIG_IGN);
Damien Miller95def091999-11-25 00:26:21 +11001251
Damien Miller95def091999-11-25 00:26:21 +11001252 /* Start listening for a socket, unless started from inetd. */
1253 if (inetd_flag) {
Darren Tucker645ab752004-06-25 13:33:20 +10001254 int fd;
1255
Damien Miller994cf142000-07-21 10:19:44 +10001256 startup_pipe = -1;
Darren Tucker645ab752004-06-25 13:33:20 +10001257 if (rexeced_flag) {
Damien Miller035a5b42004-06-26 08:16:31 +10001258 close(REEXEC_CONFIG_PASS_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001259 sock_in = sock_out = dup(STDIN_FILENO);
1260 if (!debug_flag) {
Damien Miller035a5b42004-06-26 08:16:31 +10001261 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
1262 close(REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001263 }
1264 } else {
1265 sock_in = dup(STDIN_FILENO);
1266 sock_out = dup(STDOUT_FILENO);
1267 }
Damien Millereba71ba2000-04-29 23:57:08 +10001268 /*
1269 * We intentionally do not close the descriptors 0, 1, and 2
Darren Tucker645ab752004-06-25 13:33:20 +10001270 * as our code for setting the descriptors won't work if
Damien Millereba71ba2000-04-29 23:57:08 +10001271 * ttyfd happens to be one of those.
1272 */
Darren Tucker645ab752004-06-25 13:33:20 +10001273 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1274 dup2(fd, STDIN_FILENO);
1275 dup2(fd, STDOUT_FILENO);
1276 if (fd > STDOUT_FILENO)
1277 close(fd);
1278 }
Damien Miller95def091999-11-25 00:26:21 +11001279 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
Darren Tucker645ab752004-06-25 13:33:20 +10001280 if ((options.protocol & SSH_PROTO_1) &&
1281 sensitive_data.server_key == NULL)
Ben Lindstromca42d5f2001-03-09 18:25:32 +00001282 generate_ephemeral_server_key();
Damien Miller95def091999-11-25 00:26:21 +11001283 } else {
Damien Miller34132e52000-01-14 15:45:46 +11001284 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1285 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1286 continue;
1287 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1288 fatal("Too many listen sockets. "
1289 "Enlarge MAX_LISTEN_SOCKS");
Darren Tucker96d47102005-02-09 09:53:48 +11001290 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
Damien Miller34132e52000-01-14 15:45:46 +11001291 ntop, sizeof(ntop), strport, sizeof(strport),
Darren Tucker96d47102005-02-09 09:53:48 +11001292 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
1293 error("getnameinfo failed: %.100s",
1294 (ret != EAI_SYSTEM) ? gai_strerror(ret) :
1295 strerror(errno));
Damien Miller34132e52000-01-14 15:45:46 +11001296 continue;
1297 }
1298 /* Create socket for listening. */
Damien Miller2372ace2003-05-14 13:42:23 +10001299 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1300 ai->ai_protocol);
Damien Miller34132e52000-01-14 15:45:46 +11001301 if (listen_sock < 0) {
1302 /* kernel may not support ipv6 */
1303 verbose("socket: %.100s", strerror(errno));
1304 continue;
1305 }
Damien Miller232711f2004-06-15 10:35:30 +10001306 if (set_nonblock(listen_sock) == -1) {
Darren Tuckerefa37062004-02-24 09:20:29 +11001307 close(listen_sock);
1308 continue;
1309 }
Damien Miller34132e52000-01-14 15:45:46 +11001310 /*
Damien Millere1383ce2002-09-19 11:49:37 +10001311 * Set socket options.
1312 * Allow local port reuse in TIME_WAIT.
Damien Miller34132e52000-01-14 15:45:46 +11001313 */
Damien Millere1383ce2002-09-19 11:49:37 +10001314 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1315 &on, sizeof(on)) == -1)
1316 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +11001317
Damien Miller34132e52000-01-14 15:45:46 +11001318 debug("Bind to port %s on %s.", strport, ntop);
Damien Miller95def091999-11-25 00:26:21 +11001319
Damien Miller34132e52000-01-14 15:45:46 +11001320 /* Bind the socket to the desired port. */
Damien Miller0a4e27d2001-02-18 12:36:39 +11001321 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1322 if (!ai->ai_next)
1323 error("Bind to port %s on %s failed: %.200s.",
1324 strport, ntop, strerror(errno));
Damien Miller34132e52000-01-14 15:45:46 +11001325 close(listen_sock);
1326 continue;
1327 }
1328 listen_socks[num_listen_socks] = listen_sock;
1329 num_listen_socks++;
Damien Miller95def091999-11-25 00:26:21 +11001330
Damien Miller34132e52000-01-14 15:45:46 +11001331 /* Start listening on the port. */
Damien Miller996acd22003-04-09 20:59:48 +10001332 logit("Server listening on %s port %s.", ntop, strport);
Darren Tucker3175eb92003-12-09 19:15:11 +11001333 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
Damien Miller34132e52000-01-14 15:45:46 +11001334 fatal("listen: %.100s", strerror(errno));
1335
Damien Miller95def091999-11-25 00:26:21 +11001336 }
Damien Miller34132e52000-01-14 15:45:46 +11001337 freeaddrinfo(options.listen_addrs);
1338
1339 if (!num_listen_socks)
1340 fatal("Cannot bind any address.");
1341
Ben Lindstrom98097862001-06-25 05:10:20 +00001342 if (options.protocol & SSH_PROTO_1)
1343 generate_ephemeral_server_key();
1344
1345 /*
1346 * Arrange to restart on SIGHUP. The handler needs
1347 * listen_sock.
1348 */
1349 signal(SIGHUP, sighup_handler);
1350
1351 signal(SIGTERM, sigterm_handler);
1352 signal(SIGQUIT, sigterm_handler);
1353
1354 /* Arrange SIGCHLD to be caught. */
1355 signal(SIGCHLD, main_sigchld_handler);
1356
1357 /* Write out the pid file after the sigterm handler is setup */
Damien Miller95def091999-11-25 00:26:21 +11001358 if (!debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +11001359 /*
Ben Lindstrom7ad97102000-12-06 01:42:49 +00001360 * Record our pid in /var/run/sshd.pid to make it
1361 * easier to kill the correct sshd. We don't want to
1362 * do this before the bind above because the bind will
Damien Miller5428f641999-11-25 11:54:57 +11001363 * fail if there already is a daemon, and this will
1364 * overwrite any old pid in the file.
1365 */
Damien Millerbac2d8a2000-09-05 16:13:06 +11001366 f = fopen(options.pid_file, "wb");
Darren Tuckere5327042003-07-03 13:40:44 +10001367 if (f == NULL) {
1368 error("Couldn't create pid file \"%s\": %s",
1369 options.pid_file, strerror(errno));
1370 } else {
Ben Lindstromce0f6342002-06-11 16:42:49 +00001371 fprintf(f, "%ld\n", (long) getpid());
Damien Miller95def091999-11-25 00:26:21 +11001372 fclose(f);
1373 }
1374 }
Damien Miller95def091999-11-25 00:26:21 +11001375
Damien Miller34132e52000-01-14 15:45:46 +11001376 /* setup fd set for listen */
Damien Miller37023962000-07-11 17:31:38 +10001377 fdset = NULL;
Damien Miller34132e52000-01-14 15:45:46 +11001378 maxfd = 0;
1379 for (i = 0; i < num_listen_socks; i++)
1380 if (listen_socks[i] > maxfd)
1381 maxfd = listen_socks[i];
Damien Miller37023962000-07-11 17:31:38 +10001382 /* pipes connected to unauthenticated childs */
1383 startup_pipes = xmalloc(options.max_startups * sizeof(int));
1384 for (i = 0; i < options.max_startups; i++)
1385 startup_pipes[i] = -1;
Damien Miller34132e52000-01-14 15:45:46 +11001386
Damien Miller5428f641999-11-25 11:54:57 +11001387 /*
1388 * Stay listening for connections until the system crashes or
1389 * the daemon is killed with a signal.
1390 */
Damien Miller95def091999-11-25 00:26:21 +11001391 for (;;) {
1392 if (received_sighup)
1393 sighup_restart();
Damien Miller37023962000-07-11 17:31:38 +10001394 if (fdset != NULL)
1395 xfree(fdset);
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001396 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
Damien Miller37023962000-07-11 17:31:38 +10001397 fdset = (fd_set *)xmalloc(fdsetsz);
Damien Miller34132e52000-01-14 15:45:46 +11001398 memset(fdset, 0, fdsetsz);
Damien Miller37023962000-07-11 17:31:38 +10001399
Damien Miller34132e52000-01-14 15:45:46 +11001400 for (i = 0; i < num_listen_socks; i++)
1401 FD_SET(listen_socks[i], fdset);
Damien Miller37023962000-07-11 17:31:38 +10001402 for (i = 0; i < options.max_startups; i++)
1403 if (startup_pipes[i] != -1)
1404 FD_SET(startup_pipes[i], fdset);
1405
1406 /* Wait in select until there is a connection. */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001407 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1408 if (ret < 0 && errno != EINTR)
1409 error("select: %.100s", strerror(errno));
Ben Lindstromec46e0b2001-06-09 01:27:31 +00001410 if (received_sigterm) {
Damien Miller996acd22003-04-09 20:59:48 +10001411 logit("Received signal %d; terminating.",
Ben Lindstromf8f065b2001-12-06 17:52:16 +00001412 (int) received_sigterm);
Ben Lindstromec46e0b2001-06-09 01:27:31 +00001413 close_listen_socks();
1414 unlink(options.pid_file);
1415 exit(255);
1416 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001417 if (key_used && key_do_regen) {
Ben Lindstromca42d5f2001-03-09 18:25:32 +00001418 generate_ephemeral_server_key();
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001419 key_used = 0;
1420 key_do_regen = 0;
Damien Miller34132e52000-01-14 15:45:46 +11001421 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001422 if (ret < 0)
1423 continue;
1424
Damien Miller37023962000-07-11 17:31:38 +10001425 for (i = 0; i < options.max_startups; i++)
1426 if (startup_pipes[i] != -1 &&
1427 FD_ISSET(startup_pipes[i], fdset)) {
1428 /*
1429 * the read end of the pipe is ready
1430 * if the child has closed the pipe
Ben Lindstrom4dccfa52000-12-28 16:40:05 +00001431 * after successful authentication
Damien Miller37023962000-07-11 17:31:38 +10001432 * or if the child has died
1433 */
1434 close(startup_pipes[i]);
1435 startup_pipes[i] = -1;
1436 startups--;
1437 }
Damien Miller34132e52000-01-14 15:45:46 +11001438 for (i = 0; i < num_listen_socks; i++) {
1439 if (!FD_ISSET(listen_socks[i], fdset))
Damien Miller95def091999-11-25 00:26:21 +11001440 continue;
Damien Miller37023962000-07-11 17:31:38 +10001441 fromlen = sizeof(from);
1442 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1443 &fromlen);
1444 if (newsock < 0) {
1445 if (errno != EINTR && errno != EWOULDBLOCK)
1446 error("accept: %.100s", strerror(errno));
1447 continue;
1448 }
Damien Miller232711f2004-06-15 10:35:30 +10001449 if (unset_nonblock(newsock) == -1) {
Darren Tuckerefa37062004-02-24 09:20:29 +11001450 close(newsock);
1451 continue;
1452 }
Damien Miller942da032000-08-18 13:59:06 +10001453 if (drop_connection(startups) == 1) {
1454 debug("drop connection #%d", startups);
Damien Miller37023962000-07-11 17:31:38 +10001455 close(newsock);
1456 continue;
1457 }
1458 if (pipe(startup_p) == -1) {
1459 close(newsock);
1460 continue;
1461 }
1462
Darren Tucker645ab752004-06-25 13:33:20 +10001463 if (rexec_flag && socketpair(AF_UNIX,
1464 SOCK_STREAM, 0, config_s) == -1) {
1465 error("reexec socketpair: %s",
1466 strerror(errno));
1467 close(newsock);
1468 close(startup_p[0]);
1469 close(startup_p[1]);
1470 continue;
1471 }
1472
Damien Miller37023962000-07-11 17:31:38 +10001473 for (j = 0; j < options.max_startups; j++)
1474 if (startup_pipes[j] == -1) {
1475 startup_pipes[j] = startup_p[0];
1476 if (maxfd < startup_p[0])
1477 maxfd = startup_p[0];
1478 startups++;
1479 break;
1480 }
Kevin Stevesef4eea92001-02-05 12:42:17 +00001481
Damien Miller5428f641999-11-25 11:54:57 +11001482 /*
Damien Miller37023962000-07-11 17:31:38 +10001483 * Got connection. Fork a child to handle it, unless
1484 * we are in debugging mode.
Damien Miller5428f641999-11-25 11:54:57 +11001485 */
Damien Miller37023962000-07-11 17:31:38 +10001486 if (debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +11001487 /*
Damien Miller37023962000-07-11 17:31:38 +10001488 * In debugging mode. Close the listening
1489 * socket, and start processing the
1490 * connection without forking.
Damien Miller5428f641999-11-25 11:54:57 +11001491 */
Damien Miller37023962000-07-11 17:31:38 +10001492 debug("Server will not fork when running in debugging mode.");
Damien Miller34132e52000-01-14 15:45:46 +11001493 close_listen_socks();
Damien Miller95def091999-11-25 00:26:21 +11001494 sock_in = newsock;
1495 sock_out = newsock;
Darren Tucker645ab752004-06-25 13:33:20 +10001496 close(startup_p[0]);
1497 close(startup_p[1]);
Damien Miller4d97ba22000-07-11 18:15:50 +10001498 startup_pipe = -1;
Damien Miller182ee6e2000-07-12 09:45:27 +10001499 pid = getpid();
Darren Tucker645ab752004-06-25 13:33:20 +10001500 if (rexec_flag) {
1501 send_rexec_state(config_s[0],
1502 &cfg);
1503 close(config_s[0]);
1504 }
Damien Miller95def091999-11-25 00:26:21 +11001505 break;
Damien Miller37023962000-07-11 17:31:38 +10001506 } else {
1507 /*
1508 * Normal production daemon. Fork, and have
1509 * the child process the connection. The
1510 * parent continues listening.
1511 */
1512 if ((pid = fork()) == 0) {
1513 /*
1514 * Child. Close the listening and max_startup
1515 * sockets. Start using the accepted socket.
1516 * Reinitialize logging (since our pid has
1517 * changed). We break out of the loop to handle
1518 * the connection.
1519 */
1520 startup_pipe = startup_p[1];
Ben Lindstromd84df982001-12-06 16:35:40 +00001521 close_startup_pipes();
Damien Miller37023962000-07-11 17:31:38 +10001522 close_listen_socks();
1523 sock_in = newsock;
1524 sock_out = newsock;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001525 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Darren Tucker0f56ed12004-08-29 16:38:41 +10001526 if (rexec_flag)
1527 close(config_s[0]);
Damien Miller37023962000-07-11 17:31:38 +10001528 break;
1529 }
Damien Miller95def091999-11-25 00:26:21 +11001530 }
Damien Miller37023962000-07-11 17:31:38 +10001531
1532 /* Parent. Stay in the loop. */
1533 if (pid < 0)
1534 error("fork: %.100s", strerror(errno));
1535 else
Ben Lindstromce0f6342002-06-11 16:42:49 +00001536 debug("Forked child %ld.", (long)pid);
Damien Miller37023962000-07-11 17:31:38 +10001537
1538 close(startup_p[1]);
1539
Darren Tucker645ab752004-06-25 13:33:20 +10001540 if (rexec_flag) {
1541 send_rexec_state(config_s[0], &cfg);
1542 close(config_s[0]);
1543 close(config_s[1]);
1544 }
1545
Damien Miller37023962000-07-11 17:31:38 +10001546 /* Mark that the key has been used (it was "given" to the child). */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001547 if ((options.protocol & SSH_PROTO_1) &&
1548 key_used == 0) {
1549 /* Schedule server key regeneration alarm. */
Ben Lindstrom5ade9ab2003-08-25 01:16:21 +00001550 signal(SIGALRM, key_regeneration_alarm);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001551 alarm(options.key_regeneration_time);
1552 key_used = 1;
1553 }
Damien Miller37023962000-07-11 17:31:38 +10001554
1555 arc4random_stir();
1556
1557 /* Close the new socket (the child is now taking care of it). */
1558 close(newsock);
Damien Miller95def091999-11-25 00:26:21 +11001559 }
Damien Miller34132e52000-01-14 15:45:46 +11001560 /* child process check (or debug mode) */
1561 if (num_listen_socks < 0)
1562 break;
Damien Miller95def091999-11-25 00:26:21 +11001563 }
1564 }
1565
1566 /* This is the child processing a new connection. */
Damien Miller57aae982004-03-08 23:11:25 +11001567 setproctitle("%s", "[accepted]");
Damien Miller95def091999-11-25 00:26:21 +11001568
Darren Tucker6832b832004-08-12 22:36:51 +10001569 /*
1570 * Create a new session and process group since the 4.4BSD
1571 * setlogin() affects the entire process group. We don't
1572 * want the child to be able to affect the parent.
1573 */
1574#if !defined(SSHD_ACQUIRES_CTTY)
1575 /*
1576 * If setsid is called, on some platforms sshd will later acquire a
1577 * controlling terminal which will result in "could not set
1578 * controlling tty" errors.
1579 */
1580 if (!debug_flag && !inetd_flag && setsid() < 0)
1581 error("setsid: %.100s", strerror(errno));
1582#endif
1583
Darren Tucker645ab752004-06-25 13:33:20 +10001584 if (rexec_flag) {
1585 int fd;
1586
Damien Miller035a5b42004-06-26 08:16:31 +10001587 debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1588 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001589 dup2(newsock, STDIN_FILENO);
1590 dup2(STDIN_FILENO, STDOUT_FILENO);
1591 if (startup_pipe == -1)
Damien Miller035a5b42004-06-26 08:16:31 +10001592 close(REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001593 else
Damien Miller035a5b42004-06-26 08:16:31 +10001594 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001595
Damien Miller035a5b42004-06-26 08:16:31 +10001596 dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001597 close(config_s[1]);
Darren Tuckerd8835932004-08-12 22:42:29 +10001598 if (startup_pipe != -1)
1599 close(startup_pipe);
Damien Miller035a5b42004-06-26 08:16:31 +10001600
Darren Tucker645ab752004-06-25 13:33:20 +10001601 execv(rexec_argv[0], rexec_argv);
1602
1603 /* Reexec has failed, fall back and continue */
1604 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
Damien Miller035a5b42004-06-26 08:16:31 +10001605 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
Darren Tucker645ab752004-06-25 13:33:20 +10001606 log_init(__progname, options.log_level,
1607 options.log_facility, log_stderr);
1608
1609 /* Clean up fds */
Damien Miller035a5b42004-06-26 08:16:31 +10001610 startup_pipe = REEXEC_STARTUP_PIPE_FD;
Darren Tucker645ab752004-06-25 13:33:20 +10001611 close(config_s[1]);
Damien Miller035a5b42004-06-26 08:16:31 +10001612 close(REEXEC_CONFIG_PASS_FD);
1613 newsock = sock_out = sock_in = dup(STDIN_FILENO);
Darren Tucker645ab752004-06-25 13:33:20 +10001614 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1615 dup2(fd, STDIN_FILENO);
1616 dup2(fd, STDOUT_FILENO);
1617 if (fd > STDERR_FILENO)
1618 close(fd);
1619 }
Damien Miller035a5b42004-06-26 08:16:31 +10001620 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1621 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001622 }
1623
Damien Miller5428f641999-11-25 11:54:57 +11001624 /*
1625 * Disable the key regeneration alarm. We will not regenerate the
1626 * key since we are no longer in a position to give it to anyone. We
1627 * will not restart on SIGHUP since it no longer makes sense.
1628 */
Damien Miller95def091999-11-25 00:26:21 +11001629 alarm(0);
1630 signal(SIGALRM, SIG_DFL);
1631 signal(SIGHUP, SIG_DFL);
1632 signal(SIGTERM, SIG_DFL);
1633 signal(SIGQUIT, SIG_DFL);
1634 signal(SIGCHLD, SIG_DFL);
Damien Miller4e0f5e12000-08-29 11:05:50 +11001635 signal(SIGINT, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +11001636
Damien Miller5428f641999-11-25 11:54:57 +11001637 /*
1638 * Register our connection. This turns encryption off because we do
1639 * not have a key.
1640 */
Damien Miller95def091999-11-25 00:26:21 +11001641 packet_set_connection(sock_in, sock_out);
Damien Miller9786e6e2005-07-26 21:54:56 +10001642 packet_set_server();
Damien Miller95def091999-11-25 00:26:21 +11001643
Damien Miller4f1d6b22005-05-26 11:59:32 +10001644 /* Set SO_KEEPALIVE if requested. */
1645 if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1646 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1647 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1648
Damien Miller677257f2005-06-17 12:55:03 +10001649 if ((remote_port = get_remote_port()) < 0) {
1650 debug("get_remote_port failed");
1651 cleanup_exit(255);
1652 }
Damien Miller4d3fd542005-11-05 15:13:24 +11001653
1654 /*
1655 * We use get_canonical_hostname with usedns = 0 instead of
1656 * get_remote_ipaddr here so IP options will be checked.
1657 */
1658 remote_ip = get_canonical_hostname(0);
Damien Miller95def091999-11-25 00:26:21 +11001659
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001660#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11001661 audit_connection_from(remote_ip, remote_port);
1662#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001663#ifdef LIBWRAP
Damien Miller6a4a4b92001-11-12 11:07:11 +11001664 /* Check whether logins are denied from this host. */
Darren Tucker586b0b92004-06-25 13:34:31 +10001665 if (packet_connection_is_on_socket()) {
Damien Miller95def091999-11-25 00:26:21 +11001666 struct request_info req;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001667
Ben Lindstromce89dac2001-09-12 16:58:04 +00001668 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
Damien Miller95def091999-11-25 00:26:21 +11001669 fromhost(&req);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001670
Damien Miller95def091999-11-25 00:26:21 +11001671 if (!hosts_access(&req)) {
Damien Miller6a4a4b92001-11-12 11:07:11 +11001672 debug("Connection refused by tcp wrapper");
Ben Lindstrom7de696e2001-03-29 00:45:12 +00001673 refuse(&req);
Damien Miller6a4a4b92001-11-12 11:07:11 +11001674 /* NOTREACHED */
1675 fatal("libwrap refuse returns");
Damien Miller95def091999-11-25 00:26:21 +11001676 }
Damien Miller95def091999-11-25 00:26:21 +11001677 }
Damien Miller34132e52000-01-14 15:45:46 +11001678#endif /* LIBWRAP */
Damien Miller6a4a4b92001-11-12 11:07:11 +11001679
Damien Miller95def091999-11-25 00:26:21 +11001680 /* Log the connection. */
1681 verbose("Connection from %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001682
Damien Miller5428f641999-11-25 11:54:57 +11001683 /*
Damien Miller788f2122005-11-05 15:14:59 +11001684 * We don't want to listen forever unless the other side
Damien Miller5428f641999-11-25 11:54:57 +11001685 * successfully authenticates itself. So we set up an alarm which is
1686 * cleared after successful authentication. A limit of zero
Damien Miller788f2122005-11-05 15:14:59 +11001687 * indicates no limit. Note that we don't set the alarm in debugging
Damien Miller5428f641999-11-25 11:54:57 +11001688 * mode; it is just annoying to have the server exit just when you
1689 * are about to discover the bug.
1690 */
Ben Lindstrom5ade9ab2003-08-25 01:16:21 +00001691 signal(SIGALRM, grace_alarm_handler);
Damien Miller95def091999-11-25 00:26:21 +11001692 if (!debug_flag)
1693 alarm(options.login_grace_time);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001694
Damien Millerb38eff82000-04-01 11:09:21 +10001695 sshd_exchange_identification(sock_in, sock_out);
Darren Tuckerec960f22003-08-13 20:37:05 +10001696
Damien Miller95def091999-11-25 00:26:21 +11001697 packet_set_nonblocking();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001698
Darren Tucker3e33cec2003-10-02 16:12:36 +10001699 /* allocate authentication context */
1700 authctxt = xmalloc(sizeof(*authctxt));
1701 memset(authctxt, 0, sizeof(*authctxt));
1702
Darren Tuckerf3bb4342005-03-31 21:39:25 +10001703 authctxt->loginmsg = &loginmsg;
1704
Darren Tucker3e33cec2003-10-02 16:12:36 +10001705 /* XXX global for cleanup, access from other modules */
1706 the_authctxt = authctxt;
1707
Darren Tucker5c14c732005-01-24 21:55:49 +11001708 /* prepare buffer to collect messages to display to user after login */
1709 buffer_init(&loginmsg);
1710
Ben Lindstrom943481c2002-03-22 03:43:46 +00001711 if (use_privsep)
Darren Tucker3e33cec2003-10-02 16:12:36 +10001712 if (privsep_preauth(authctxt) == 1)
Ben Lindstrom943481c2002-03-22 03:43:46 +00001713 goto authenticated;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001714
Damien Miller396691a2000-01-20 22:44:08 +11001715 /* perform the key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001716 /* authenticate user and start session */
Damien Millerefb4afe2000-04-12 18:45:05 +10001717 if (compat20) {
1718 do_ssh2_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001719 do_authentication2(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001720 } else {
1721 do_ssh1_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001722 do_authentication(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001723 }
Ben Lindstrom943481c2002-03-22 03:43:46 +00001724 /*
1725 * If we use privilege separation, the unprivileged child transfers
1726 * the current keystate and exits
1727 */
1728 if (use_privsep) {
Ben Lindstrom7339b2a2002-05-15 16:25:01 +00001729 mm_send_keystate(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001730 exit(0);
Ben Lindstrom943481c2002-03-22 03:43:46 +00001731 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001732
1733 authenticated:
Damien Miller7bff1a92005-12-24 14:59:12 +11001734 /*
1735 * Cancel the alarm we set to limit the time taken for
1736 * authentication.
1737 */
1738 alarm(0);
1739 signal(SIGALRM, SIG_DFL);
1740 if (startup_pipe != -1) {
1741 close(startup_pipe);
1742 startup_pipe = -1;
1743 }
1744
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001745#ifdef SSH_AUDIT_EVENTS
1746 audit_event(SSH_AUTH_SUCCESS);
Darren Tucker269a1ea2005-02-03 00:20:53 +11001747#endif
1748
Ben Lindstrom6328ab32002-03-22 02:54:23 +00001749 /*
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001750 * In privilege separation, we fork another child and prepare
1751 * file descriptor passing.
1752 */
1753 if (use_privsep) {
Ben Lindstrom943481c2002-03-22 03:43:46 +00001754 privsep_postauth(authctxt);
1755 /* the monitor process [priv] will not return */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001756 if (!compat20)
1757 destroy_sensitive_data();
1758 }
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001759
Darren Tucker3e33cec2003-10-02 16:12:36 +10001760 /* Start session. */
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001761 do_authenticated(authctxt);
1762
Damien Miller3a5b0232002-03-13 13:19:42 +11001763 /* The connection has been terminated. */
1764 verbose("Closing connection to %.100s", remote_ip);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001765
Damien Millerbeb4ba51999-12-28 15:09:35 +11001766#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +10001767 if (options.use_pam)
1768 finish_pam();
Damien Millerbeb4ba51999-12-28 15:09:35 +11001769#endif /* USE_PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001770
Darren Tucker2b59a6d2005-03-06 22:38:51 +11001771#ifdef SSH_AUDIT_EVENTS
1772 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE));
1773#endif
1774
Damien Miller95def091999-11-25 00:26:21 +11001775 packet_close();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001776
1777 if (use_privsep)
1778 mm_terminate();
1779
Damien Miller95def091999-11-25 00:26:21 +11001780 exit(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001781}
1782
Damien Miller95def091999-11-25 00:26:21 +11001783/*
Ben Lindstromabcb1452002-03-22 01:10:21 +00001784 * Decrypt session_key_int using our private server key and private host key
1785 * (key with larger modulus first).
1786 */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001787int
Ben Lindstromabcb1452002-03-22 01:10:21 +00001788ssh1_session_key(BIGNUM *session_key_int)
1789{
1790 int rsafail = 0;
1791
1792 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
1793 /* Server key has bigger modulus. */
1794 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1795 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1796 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1797 get_remote_ipaddr(),
1798 BN_num_bits(sensitive_data.server_key->rsa->n),
1799 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1800 SSH_KEY_BITS_RESERVED);
1801 }
1802 if (rsa_private_decrypt(session_key_int, session_key_int,
1803 sensitive_data.server_key->rsa) <= 0)
1804 rsafail++;
1805 if (rsa_private_decrypt(session_key_int, session_key_int,
1806 sensitive_data.ssh1_host_key->rsa) <= 0)
1807 rsafail++;
1808 } else {
1809 /* Host key has bigger modulus (or they are equal). */
1810 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1811 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1812 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1813 get_remote_ipaddr(),
1814 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1815 BN_num_bits(sensitive_data.server_key->rsa->n),
1816 SSH_KEY_BITS_RESERVED);
1817 }
1818 if (rsa_private_decrypt(session_key_int, session_key_int,
1819 sensitive_data.ssh1_host_key->rsa) < 0)
1820 rsafail++;
1821 if (rsa_private_decrypt(session_key_int, session_key_int,
1822 sensitive_data.server_key->rsa) < 0)
1823 rsafail++;
1824 }
1825 return (rsafail);
1826}
1827/*
Damien Miller396691a2000-01-20 22:44:08 +11001828 * SSH1 key exchange
Damien Miller95def091999-11-25 00:26:21 +11001829 */
Ben Lindstrombba81212001-06-25 05:01:22 +00001830static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001831do_ssh1_kex(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001832{
Damien Miller95def091999-11-25 00:26:21 +11001833 int i, len;
Damien Miller7650bc62001-01-30 09:27:26 +11001834 int rsafail = 0;
Damien Miller95def091999-11-25 00:26:21 +11001835 BIGNUM *session_key_int;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001836 u_char session_key[SSH_SESSION_KEY_LENGTH];
1837 u_char cookie[8];
1838 u_int cipher_type, auth_mask, protocol_flags;
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001839 u_int32_t rnd = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001840
Damien Miller5428f641999-11-25 11:54:57 +11001841 /*
1842 * Generate check bytes that the client must send back in the user
1843 * packet in order for it to be accepted; this is used to defy ip
1844 * spoofing attacks. Note that this only works against somebody
1845 * doing IP spoofing from a remote machine; any machine on the local
1846 * network can still see outgoing packets and catch the random
1847 * cookie. This only affects rhosts authentication, and this is one
1848 * of the reasons why it is inherently insecure.
1849 */
Damien Miller95def091999-11-25 00:26:21 +11001850 for (i = 0; i < 8; i++) {
1851 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001852 rnd = arc4random();
1853 cookie[i] = rnd & 0xff;
1854 rnd >>= 8;
Damien Miller95def091999-11-25 00:26:21 +11001855 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001856
Damien Miller5428f641999-11-25 11:54:57 +11001857 /*
1858 * Send our public key. We include in the packet 64 bits of random
1859 * data that must be matched in the reply in order to prevent IP
1860 * spoofing.
1861 */
Damien Miller95def091999-11-25 00:26:21 +11001862 packet_start(SSH_SMSG_PUBLIC_KEY);
1863 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001864 packet_put_char(cookie[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001865
Damien Miller95def091999-11-25 00:26:21 +11001866 /* Store our public server RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001867 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1868 packet_put_bignum(sensitive_data.server_key->rsa->e);
1869 packet_put_bignum(sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001870
Damien Miller95def091999-11-25 00:26:21 +11001871 /* Store our public host RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001872 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1873 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1874 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001875
Damien Miller95def091999-11-25 00:26:21 +11001876 /* Put protocol flags. */
1877 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001878
Damien Miller95def091999-11-25 00:26:21 +11001879 /* Declare which ciphers we support. */
Damien Miller874d77b2000-10-14 16:23:11 +11001880 packet_put_int(cipher_mask_ssh1(0));
Damien Miller95def091999-11-25 00:26:21 +11001881
1882 /* Declare supported authentication types. */
1883 auth_mask = 0;
Damien Miller95def091999-11-25 00:26:21 +11001884 if (options.rhosts_rsa_authentication)
1885 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1886 if (options.rsa_authentication)
1887 auth_mask |= 1 << SSH_AUTH_RSA;
Ben Lindstrom551ea372001-06-05 18:56:16 +00001888 if (options.challenge_response_authentication == 1)
Damien Miller95def091999-11-25 00:26:21 +11001889 auth_mask |= 1 << SSH_AUTH_TIS;
Damien Miller95def091999-11-25 00:26:21 +11001890 if (options.password_authentication)
1891 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1892 packet_put_int(auth_mask);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001893
Damien Miller95def091999-11-25 00:26:21 +11001894 /* Send the packet and wait for it to be sent. */
1895 packet_send();
1896 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001897
Damien Miller0bc1bd82000-11-13 22:57:25 +11001898 debug("Sent %d bit server key and %d bit host key.",
1899 BN_num_bits(sensitive_data.server_key->rsa->n),
1900 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001901
Damien Miller95def091999-11-25 00:26:21 +11001902 /* Read clients reply (cipher type and session key). */
Damien Millerdff50992002-01-22 23:16:32 +11001903 packet_read_expect(SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001904
Damien Miller50945fa1999-12-09 10:31:37 +11001905 /* Get cipher type and check whether we accept this. */
Damien Miller95def091999-11-25 00:26:21 +11001906 cipher_type = packet_get_char();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001907
Damien Miller874d77b2000-10-14 16:23:11 +11001908 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
Damien Miller50945fa1999-12-09 10:31:37 +11001909 packet_disconnect("Warning: client selects unsupported cipher.");
1910
Damien Miller95def091999-11-25 00:26:21 +11001911 /* Get check bytes from the packet. These must match those we
1912 sent earlier with the public key packet. */
1913 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001914 if (cookie[i] != packet_get_char())
Damien Miller95def091999-11-25 00:26:21 +11001915 packet_disconnect("IP Spoofing check bytes do not match.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001916
Damien Miller95def091999-11-25 00:26:21 +11001917 debug("Encryption type: %.200s", cipher_name(cipher_type));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001918
Damien Miller95def091999-11-25 00:26:21 +11001919 /* Get the encrypted integer. */
Damien Millerda755162002-01-22 23:09:22 +11001920 if ((session_key_int = BN_new()) == NULL)
1921 fatal("do_ssh1_kex: BN_new failed");
Damien Millerd432ccf2002-01-22 23:14:44 +11001922 packet_get_bignum(session_key_int);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001923
Damien Miller95def091999-11-25 00:26:21 +11001924 protocol_flags = packet_get_int();
1925 packet_set_protocol_flags(protocol_flags);
Damien Miller48b03fc2002-01-22 23:11:40 +11001926 packet_check_eom();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001927
Ben Lindstromabcb1452002-03-22 01:10:21 +00001928 /* Decrypt session_key_int using host/server keys */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001929 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1930
Damien Miller5428f641999-11-25 11:54:57 +11001931 /*
1932 * Extract session key from the decrypted integer. The key is in the
1933 * least significant 256 bits of the integer; the first byte of the
1934 * key is in the highest bits.
1935 */
Damien Miller7650bc62001-01-30 09:27:26 +11001936 if (!rsafail) {
1937 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1938 len = BN_num_bytes(session_key_int);
Damien Millereccb9de2005-06-17 12:59:34 +10001939 if (len < 0 || (u_int)len > sizeof(session_key)) {
Damien Miller7650bc62001-01-30 09:27:26 +11001940 error("do_connection: bad session key len from %s: "
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001941 "session_key_int %d > sizeof(session_key) %lu",
1942 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
Damien Miller7650bc62001-01-30 09:27:26 +11001943 rsafail++;
1944 } else {
1945 memset(session_key, 0, sizeof(session_key));
1946 BN_bn2bin(session_key_int,
1947 session_key + sizeof(session_key) - len);
Ben Lindstromeb648a72001-03-05 06:00:29 +00001948
Darren Tuckere14e0052004-05-13 16:30:44 +10001949 derive_ssh1_session_id(
Darren Tuckerfc959702004-07-17 16:12:08 +10001950 sensitive_data.ssh1_host_key->rsa->n,
Darren Tuckere14e0052004-05-13 16:30:44 +10001951 sensitive_data.server_key->rsa->n,
1952 cookie, session_id);
Ben Lindstromeb648a72001-03-05 06:00:29 +00001953 /*
1954 * Xor the first 16 bytes of the session key with the
1955 * session id.
1956 */
1957 for (i = 0; i < 16; i++)
1958 session_key[i] ^= session_id[i];
Damien Miller7650bc62001-01-30 09:27:26 +11001959 }
1960 }
1961 if (rsafail) {
Ben Lindstromeb648a72001-03-05 06:00:29 +00001962 int bytes = BN_num_bytes(session_key_int);
Ben Lindstrom13c5d3b2002-02-26 18:00:48 +00001963 u_char *buf = xmalloc(bytes);
Ben Lindstromeb648a72001-03-05 06:00:29 +00001964 MD5_CTX md;
1965
Damien Miller996acd22003-04-09 20:59:48 +10001966 logit("do_connection: generating a fake encryption key");
Ben Lindstromeb648a72001-03-05 06:00:29 +00001967 BN_bn2bin(session_key_int, buf);
1968 MD5_Init(&md);
1969 MD5_Update(&md, buf, bytes);
1970 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1971 MD5_Final(session_key, &md);
1972 MD5_Init(&md);
1973 MD5_Update(&md, session_key, 16);
1974 MD5_Update(&md, buf, bytes);
1975 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1976 MD5_Final(session_key + 16, &md);
1977 memset(buf, 0, bytes);
1978 xfree(buf);
Ben Lindstrom941ac822001-03-05 06:25:23 +00001979 for (i = 0; i < 16; i++)
1980 session_id[i] = session_key[i] ^ session_key[i + 16];
Damien Miller7650bc62001-01-30 09:27:26 +11001981 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001982 /* Destroy the private and public keys. No longer. */
Damien Miller3a5b0232002-03-13 13:19:42 +11001983 destroy_sensitive_data();
Ben Lindstromeb648a72001-03-05 06:00:29 +00001984
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001985 if (use_privsep)
1986 mm_ssh1_session_id(session_id);
1987
Damien Miller396691a2000-01-20 22:44:08 +11001988 /* Destroy the decrypted integer. It is no longer needed. */
1989 BN_clear_free(session_key_int);
1990
Damien Miller95def091999-11-25 00:26:21 +11001991 /* Set the session key. From this on all communications will be encrypted. */
1992 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001993
Damien Miller95def091999-11-25 00:26:21 +11001994 /* Destroy our copy of the session key. It is no longer needed. */
1995 memset(session_key, 0, sizeof(session_key));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001996
Damien Miller95def091999-11-25 00:26:21 +11001997 debug("Received session key; encryption turned on.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001998
Ben Lindstromf666fec2002-06-06 19:51:58 +00001999 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
Damien Miller95def091999-11-25 00:26:21 +11002000 packet_start(SSH_SMSG_SUCCESS);
2001 packet_send();
2002 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002003}
Damien Millerefb4afe2000-04-12 18:45:05 +10002004
2005/*
2006 * SSH2 key exchange: diffie-hellman-group1-sha1
2007 */
Ben Lindstrombba81212001-06-25 05:01:22 +00002008static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00002009do_ssh2_kex(void)
Damien Millerefb4afe2000-04-12 18:45:05 +10002010{
Damien Millerefb4afe2000-04-12 18:45:05 +10002011 Kex *kex;
Damien Millerefb4afe2000-04-12 18:45:05 +10002012
Damien Miller78928792000-04-12 20:17:38 +10002013 if (options.ciphers != NULL) {
Damien Miller4af51302000-04-16 11:18:38 +10002014 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
Damien Miller78928792000-04-12 20:17:38 +10002015 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
2016 }
Damien Millera0ff4662001-03-30 10:49:35 +10002017 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
2018 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
2019 myproposal[PROPOSAL_ENC_ALGS_STOC] =
2020 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
2021
Ben Lindstrom06b33aa2001-02-15 03:01:59 +00002022 if (options.macs != NULL) {
2023 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2024 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2025 }
Damien Miller9786e6e2005-07-26 21:54:56 +10002026 if (options.compression == COMP_NONE) {
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002027 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2028 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
Damien Miller9786e6e2005-07-26 21:54:56 +10002029 } else if (options.compression == COMP_DELAYED) {
2030 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2031 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002032 }
Damien Miller9786e6e2005-07-26 21:54:56 +10002033
Damien Miller0bc1bd82000-11-13 22:57:25 +11002034 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
2035
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002036 /* start key exchange */
Ben Lindstrom238abf62001-04-04 17:52:53 +00002037 kex = kex_setup(myproposal);
Damien Miller8e7fb332003-02-24 12:03:03 +11002038 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
Damien Millerf675fc42004-06-15 10:30:09 +10002039 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
Damien Miller8e7fb332003-02-24 12:03:03 +11002040 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002041 kex->server = 1;
2042 kex->client_version_string=client_version_string;
2043 kex->server_version_string=server_version_string;
2044 kex->load_host_key=&get_hostkey_by_type;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002045 kex->host_key_index=&get_hostkey_index;
Damien Millerefb4afe2000-04-12 18:45:05 +10002046
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002047 xxx_kex = kex;
2048
Ben Lindstrombe2cc432001-04-04 23:46:07 +00002049 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
Damien Miller874d77b2000-10-14 16:23:11 +11002050
Ben Lindstrom2d90e002001-04-04 02:00:54 +00002051 session_id2 = kex->session_id;
2052 session_id2_len = kex->session_id_len;
2053
Damien Miller874d77b2000-10-14 16:23:11 +11002054#ifdef DEBUG_KEXDH
2055 /* send 1st encrypted/maced/compressed message */
2056 packet_start(SSH2_MSG_IGNORE);
2057 packet_put_cstring("markus");
2058 packet_send();
2059 packet_write_wait();
2060#endif
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002061 debug("KEX done");
Damien Millerefb4afe2000-04-12 18:45:05 +10002062}
Darren Tucker3e33cec2003-10-02 16:12:36 +10002063
2064/* server specific fatal cleanup */
2065void
2066cleanup_exit(int i)
2067{
2068 if (the_authctxt)
2069 do_cleanup(the_authctxt);
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002070#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11002071 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
2072 if (!use_privsep || mm_is_monitor())
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002073 audit_event(SSH_CONNECTION_ABANDON);
Darren Tucker269a1ea2005-02-03 00:20:53 +11002074#endif
Darren Tucker3e33cec2003-10-02 16:12:36 +10002075 _exit(i);
2076}