blob: aef4db109fba0fa16d4d70cd73cd3cf8cd089faa [file] [log] [blame]
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 Millerb24c2f82006-03-15 12:04:36 +110045RCSID("$OpenBSD: sshd.c,v 1.325 2006/03/13 08:16:00 djm Exp $");
Damien Miller17e91c02006-03-15 11:28:34 +110046
Damien Miller9cf6d072006-03-15 11:29:24 +110047#include <sys/types.h>
Damien Millerf17883e2006-03-15 11:45:54 +110048#ifdef HAVE_SYS_STAT_H
49# include <sys/stat.h>
50#endif
51#include <sys/ioctl.h>
Damien Miller9cf6d072006-03-15 11:29:24 +110052#include <sys/wait.h>
Damien Miller03e20032006-03-15 11:16:59 +110053
Damien Miller6645e7a2006-03-15 14:42:54 +110054#ifdef HAVE_PATHS_H
Damien Miller03e20032006-03-15 11:16:59 +110055#include <paths.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110056#endif
Damien Miller6ff3cad2006-03-15 11:52:09 +110057#include <signal.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100058
Ben Lindstrom226cfa02001-01-22 05:34:40 +000059#include <openssl/dh.h>
60#include <openssl/bn.h>
Damien Miller6a47f302002-02-13 13:55:06 +110061#include <openssl/md5.h>
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000062#include <openssl/rand.h>
Kevin Steves0ea1d9d2002-04-25 18:17:04 +000063#ifdef HAVE_SECUREWARE
64#include <sys/security.h>
65#include <prot.h>
66#endif
Ben Lindstrom226cfa02001-01-22 05:34:40 +000067
68#include "ssh.h"
69#include "ssh1.h"
70#include "ssh2.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100071#include "xmalloc.h"
72#include "rsa.h"
Ben Lindstromd95c09c2001-02-18 19:13:33 +000073#include "sshpty.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100074#include "packet.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000075#include "log.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100076#include "servconf.h"
77#include "uidswap.h"
78#include "compat.h"
Damien Millerb38eff82000-04-01 11:09:21 +100079#include "buffer.h"
Darren Tucker645ab752004-06-25 13:33:20 +100080#include "bufaux.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000081#include "cipher.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100082#include "kex.h"
Damien Millerb38eff82000-04-01 11:09:21 +100083#include "key.h"
Damien Miller874d77b2000-10-14 16:23:11 +110084#include "dh.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100085#include "myproposal.h"
Damien Millereba71ba2000-04-29 23:57:08 +100086#include "authfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000087#include "pathnames.h"
88#include "atomicio.h"
89#include "canohost.h"
90#include "auth.h"
91#include "misc.h"
Darren Tucker645ab752004-06-25 13:33:20 +100092#include "msg.h"
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +000093#include "dispatch.h"
Ben Lindstrom1bae4042001-10-03 17:46:39 +000094#include "channels.h"
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +000095#include "session.h"
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000096#include "monitor_mm.h"
97#include "monitor.h"
98#include "monitor_wrap.h"
99#include "monitor_fdpass.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000100
101#ifdef LIBWRAP
102#include <tcpd.h>
103#include <syslog.h>
104int allow_severity = LOG_INFO;
105int deny_severity = LOG_WARNING;
106#endif /* LIBWRAP */
107
108#ifndef O_NOCTTY
109#define O_NOCTTY 0
110#endif
111
Damien Miller035a5b42004-06-26 08:16:31 +1000112/* Re-exec fds */
113#define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
114#define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
115#define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
116#define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
117
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000118extern char *__progname;
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000119
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000120/* Server configuration options. */
121ServerOptions options;
122
123/* Name of the server configuration file. */
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000124char *config_file_name = _PATH_SERVER_CONFIG_FILE;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000125
Damien Miller4af51302000-04-16 11:18:38 +1000126/*
Damien Miller95def091999-11-25 00:26:21 +1100127 * Debug mode flag. This can be set on the command line. If debug
128 * mode is enabled, extra debugging output will be sent to the system
129 * log, the daemon will not go to background, and will exit after processing
130 * the first connection.
131 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000132int debug_flag = 0;
133
Ben Lindstrom794325a2001-08-06 21:09:07 +0000134/* Flag indicating that the daemon should only test the configuration and keys. */
135int test_flag = 0;
136
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000137/* Flag indicating that the daemon is being started from inetd. */
138int inetd_flag = 0;
139
Ben Lindstromc72745a2000-12-02 19:03:54 +0000140/* Flag indicating that sshd should not detach and become a daemon. */
141int no_daemon_flag = 0;
142
Damien Miller5ce662a1999-11-11 17:57:39 +1100143/* debug goes to stderr unless inetd_flag is set */
144int log_stderr = 0;
145
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000146/* Saved arguments to main(). */
147char **saved_argv;
Damien Millerb8c656e2000-06-28 15:22:41 +1000148int saved_argc;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000149
Darren Tucker645ab752004-06-25 13:33:20 +1000150/* re-exec */
151int rexeced_flag = 0;
152int rexec_flag = 1;
153int rexec_argc = 0;
154char **rexec_argv;
155
Damien Miller5428f641999-11-25 11:54:57 +1100156/*
Damien Miller34132e52000-01-14 15:45:46 +1100157 * The sockets that the server is listening; this is used in the SIGHUP
158 * signal handler.
Damien Miller5428f641999-11-25 11:54:57 +1100159 */
Damien Miller34132e52000-01-14 15:45:46 +1100160#define MAX_LISTEN_SOCKS 16
161int listen_socks[MAX_LISTEN_SOCKS];
162int num_listen_socks = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000163
Damien Miller5428f641999-11-25 11:54:57 +1100164/*
165 * the client's version string, passed by sshd2 in compat mode. if != NULL,
166 * sshd will skip the version-number exchange
167 */
Damien Miller95def091999-11-25 00:26:21 +1100168char *client_version_string = NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000169char *server_version_string = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000170
Ben Lindstrom8ac91062001-04-04 17:57:54 +0000171/* for rekeying XXX fixme */
172Kex *xxx_kex;
173
Damien Miller5428f641999-11-25 11:54:57 +1100174/*
175 * Any really sensitive data in the application is contained in this
176 * structure. The idea is that this structure could be locked into memory so
177 * that the pages do not get written into swap. However, there are some
178 * problems. The private key contains BIGNUMs, and we do not (in principle)
179 * have access to the internals of them, and locking just the structure is
180 * not very useful. Currently, memory locking is not implemented.
181 */
Damien Miller95def091999-11-25 00:26:21 +1100182struct {
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000183 Key *server_key; /* ephemeral server key */
Damien Miller0bc1bd82000-11-13 22:57:25 +1100184 Key *ssh1_host_key; /* ssh1 host key */
185 Key **host_keys; /* all private host keys */
186 int have_ssh1_key;
187 int have_ssh2_key;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000188 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000189} sensitive_data;
190
Damien Miller5428f641999-11-25 11:54:57 +1100191/*
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000192 * Flag indicating whether the RSA server key needs to be regenerated.
193 * Is set in the SIGALRM handler and cleared when the key is regenerated.
Damien Miller5428f641999-11-25 11:54:57 +1100194 */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000195static volatile sig_atomic_t key_do_regen = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000196
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000197/* This is set to true when a signal is received. */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000198static volatile sig_atomic_t received_sighup = 0;
199static volatile sig_atomic_t received_sigterm = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000200
Damien Millerb38eff82000-04-01 11:09:21 +1000201/* session identifier, used by RSA-auth */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000202u_char session_id[16];
Damien Millerb38eff82000-04-01 11:09:21 +1000203
Damien Millereba71ba2000-04-29 23:57:08 +1000204/* same for ssh2 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000205u_char *session_id2 = NULL;
Darren Tucker502d3842003-06-28 12:38:01 +1000206u_int session_id2_len = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000207
Damien Miller942da032000-08-18 13:59:06 +1000208/* record remote hostname or ip */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000209u_int utmp_len = MAXHOSTNAMELEN;
Damien Miller942da032000-08-18 13:59:06 +1000210
Ben Lindstromd84df982001-12-06 16:35:40 +0000211/* options.max_startup sized array of fd ints */
212int *startup_pipes = NULL;
213int startup_pipe; /* in child */
214
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000215/* variables used for privilege separation */
Damien Miller8e7fb332003-02-24 12:03:03 +1100216int use_privsep;
Darren Tuckera8be9e22004-02-06 16:40:27 +1100217struct monitor *pmonitor = NULL;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000218
Darren Tucker3e33cec2003-10-02 16:12:36 +1000219/* global authentication context */
220Authctxt *the_authctxt = NULL;
221
Darren Tucker09991742004-07-17 17:05:14 +1000222/* message to be displayed after login */
223Buffer loginmsg;
224
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000225/* Prototypes for various functions defined later in this file. */
Ben Lindstrombba81212001-06-25 05:01:22 +0000226void destroy_sensitive_data(void);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000227void demote_sensitive_data(void);
Damien Miller98c7ad62000-03-09 21:27:49 +1100228
Ben Lindstrombba81212001-06-25 05:01:22 +0000229static void do_ssh1_kex(void);
230static void do_ssh2_kex(void);
Damien Miller874d77b2000-10-14 16:23:11 +1100231
Damien Miller98c7ad62000-03-09 21:27:49 +1100232/*
Damien Miller34132e52000-01-14 15:45:46 +1100233 * Close all listening sockets
234 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000235static void
Damien Miller34132e52000-01-14 15:45:46 +1100236close_listen_socks(void)
237{
238 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000239
Damien Miller34132e52000-01-14 15:45:46 +1100240 for (i = 0; i < num_listen_socks; i++)
241 close(listen_socks[i]);
242 num_listen_socks = -1;
243}
244
Ben Lindstromd84df982001-12-06 16:35:40 +0000245static void
246close_startup_pipes(void)
247{
248 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000249
Ben Lindstromd84df982001-12-06 16:35:40 +0000250 if (startup_pipes)
251 for (i = 0; i < options.max_startups; i++)
252 if (startup_pipes[i] != -1)
253 close(startup_pipes[i]);
254}
255
Damien Miller34132e52000-01-14 15:45:46 +1100256/*
Damien Miller95def091999-11-25 00:26:21 +1100257 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
258 * the effect is to reread the configuration file (and to regenerate
259 * the server key).
260 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000261static void
Damien Miller95def091999-11-25 00:26:21 +1100262sighup_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000263{
Ben Lindstrom07958482001-12-06 16:19:01 +0000264 int save_errno = errno;
265
Damien Miller95def091999-11-25 00:26:21 +1100266 received_sighup = 1;
267 signal(SIGHUP, sighup_handler);
Ben Lindstrom07958482001-12-06 16:19:01 +0000268 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000269}
270
Damien Miller95def091999-11-25 00:26:21 +1100271/*
272 * Called from the main program after receiving SIGHUP.
273 * Restarts the server.
274 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000275static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000276sighup_restart(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000277{
Damien Miller996acd22003-04-09 20:59:48 +1000278 logit("Received SIGHUP; restarting.");
Damien Miller34132e52000-01-14 15:45:46 +1100279 close_listen_socks();
Ben Lindstromd84df982001-12-06 16:35:40 +0000280 close_startup_pipes();
Damien Miller95def091999-11-25 00:26:21 +1100281 execv(saved_argv[0], saved_argv);
Damien Miller996acd22003-04-09 20:59:48 +1000282 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
Ben Lindstrom822b6342002-06-23 21:38:49 +0000283 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100284 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000285}
286
Damien Miller95def091999-11-25 00:26:21 +1100287/*
288 * Generic signal handler for terminating signals in the master daemon.
Damien Miller95def091999-11-25 00:26:21 +1100289 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000290static void
Damien Miller95def091999-11-25 00:26:21 +1100291sigterm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000292{
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000293 received_sigterm = sig;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000294}
295
Damien Miller95def091999-11-25 00:26:21 +1100296/*
297 * SIGCHLD handler. This is called whenever a child dies. This will then
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000298 * reap any zombies left by exited children.
Damien Miller95def091999-11-25 00:26:21 +1100299 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000300static void
Damien Miller95def091999-11-25 00:26:21 +1100301main_sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000302{
Damien Miller95def091999-11-25 00:26:21 +1100303 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000304 pid_t pid;
Damien Miller95def091999-11-25 00:26:21 +1100305 int status;
Damien Miller431f66b1999-11-21 18:31:57 +1100306
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000307 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
308 (pid < 0 && errno == EINTR))
Damien Miller95def091999-11-25 00:26:21 +1100309 ;
Damien Miller431f66b1999-11-21 18:31:57 +1100310
Damien Miller95def091999-11-25 00:26:21 +1100311 signal(SIGCHLD, main_sigchld_handler);
312 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000313}
314
Damien Miller95def091999-11-25 00:26:21 +1100315/*
316 * Signal handler for the alarm after the login grace period has expired.
317 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000318static void
Damien Miller95def091999-11-25 00:26:21 +1100319grace_alarm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000320{
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000321 /* XXX no idea how fix this signal handler */
322
Darren Tuckera8be9e22004-02-06 16:40:27 +1100323 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
324 kill(pmonitor->m_pid, SIGALRM);
325
Damien Miller95def091999-11-25 00:26:21 +1100326 /* Log error and exit. */
Damien Millerd27a76d2002-09-27 13:22:31 +1000327 fatal("Timeout before authentication for %s", get_remote_ipaddr());
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000328}
329
Damien Miller95def091999-11-25 00:26:21 +1100330/*
Damien Miller95def091999-11-25 00:26:21 +1100331 * Signal handler for the key regeneration alarm. Note that this
332 * alarm only occurs in the daemon waiting for connections, and it does not
333 * do anything with the private key or random state before forking.
334 * Thus there should be no concurrency control/asynchronous execution
335 * problems.
336 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000337static void
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000338generate_ephemeral_server_key(void)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100339{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000340 u_int32_t rnd = 0;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000341 int i;
342
Ben Lindstroma3700052001-04-05 23:26:32 +0000343 verbose("Generating %s%d bit RSA key.",
Damien Millerff75ac42001-03-30 10:50:32 +1000344 sensitive_data.server_key ? "new " : "", options.server_key_bits);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100345 if (sensitive_data.server_key != NULL)
346 key_free(sensitive_data.server_key);
Ben Lindstroma3700052001-04-05 23:26:32 +0000347 sensitive_data.server_key = key_generate(KEY_RSA1,
Damien Millerff75ac42001-03-30 10:50:32 +1000348 options.server_key_bits);
349 verbose("RSA key generation complete.");
Ben Lindstromeb648a72001-03-05 06:00:29 +0000350
351 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
352 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000353 rnd = arc4random();
354 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
355 rnd >>= 8;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000356 }
357 arc4random_stir();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100358}
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000359
Ben Lindstrombba81212001-06-25 05:01:22 +0000360static void
Damien Miller95def091999-11-25 00:26:21 +1100361key_regeneration_alarm(int sig)
362{
363 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000364
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000365 signal(SIGALRM, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +1100366 errno = save_errno;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000367 key_do_regen = 1;
Damien Miller95def091999-11-25 00:26:21 +1100368}
369
Ben Lindstrombba81212001-06-25 05:01:22 +0000370static void
Damien Millerb38eff82000-04-01 11:09:21 +1000371sshd_exchange_identification(int sock_in, int sock_out)
372{
Damien Millereccb9de2005-06-17 12:59:34 +1000373 u_int i;
374 int mismatch;
Damien Millerb38eff82000-04-01 11:09:21 +1000375 int remote_major, remote_minor;
Damien Miller78928792000-04-12 20:17:38 +1000376 int major, minor;
Damien Millerb38eff82000-04-01 11:09:21 +1000377 char *s;
378 char buf[256]; /* Must not be larger than remote_version. */
379 char remote_version[256]; /* Must be at least as big as buf. */
380
Damien Miller78928792000-04-12 20:17:38 +1000381 if ((options.protocol & SSH_PROTO_1) &&
382 (options.protocol & SSH_PROTO_2)) {
383 major = PROTOCOL_MAJOR_1;
384 minor = 99;
385 } else if (options.protocol & SSH_PROTO_2) {
386 major = PROTOCOL_MAJOR_2;
387 minor = PROTOCOL_MINOR_2;
388 } else {
389 major = PROTOCOL_MAJOR_1;
390 minor = PROTOCOL_MINOR_1;
391 }
392 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
Damien Millerb38eff82000-04-01 11:09:21 +1000393 server_version_string = xstrdup(buf);
394
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000395 /* Send our protocol version identification. */
396 if (atomicio(vwrite, sock_out, server_version_string,
397 strlen(server_version_string))
398 != strlen(server_version_string)) {
399 logit("Could not write ident string to %s", get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000400 cleanup_exit(255);
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000401 }
402
403 /* Read other sides version identification. */
404 memset(buf, 0, sizeof(buf));
405 for (i = 0; i < sizeof(buf) - 1; i++) {
406 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
407 logit("Did not receive identification string from %s",
408 get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000409 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000410 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000411 if (buf[i] == '\r') {
412 buf[i] = 0;
413 /* Kludge for F-Secure Macintosh < 1.0.2 */
414 if (i == 12 &&
415 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
Damien Millerb38eff82000-04-01 11:09:21 +1000416 break;
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000417 continue;
Damien Millerb38eff82000-04-01 11:09:21 +1000418 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000419 if (buf[i] == '\n') {
420 buf[i] = 0;
421 break;
422 }
Damien Millerb38eff82000-04-01 11:09:21 +1000423 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000424 buf[sizeof(buf) - 1] = 0;
425 client_version_string = xstrdup(buf);
Damien Millerb38eff82000-04-01 11:09:21 +1000426
427 /*
428 * Check that the versions match. In future this might accept
429 * several versions and set appropriate flags to handle them.
430 */
431 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
432 &remote_major, &remote_minor, remote_version) != 3) {
Damien Miller4af51302000-04-16 11:18:38 +1000433 s = "Protocol mismatch.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000434 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Millerb38eff82000-04-01 11:09:21 +1000435 close(sock_in);
436 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000437 logit("Bad protocol version identification '%.100s' from %s",
Damien Millerb38eff82000-04-01 11:09:21 +1000438 client_version_string, get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000439 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000440 }
441 debug("Client protocol version %d.%d; client software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100442 remote_major, remote_minor, remote_version);
Damien Millerb38eff82000-04-01 11:09:21 +1000443
Damien Millerefb4afe2000-04-12 18:45:05 +1000444 compat_datafellows(remote_version);
445
Damien Millere9264972002-09-30 11:59:21 +1000446 if (datafellows & SSH_BUG_PROBE) {
Damien Miller996acd22003-04-09 20:59:48 +1000447 logit("probed from %s with %s. Don't panic.",
Damien Millere9264972002-09-30 11:59:21 +1000448 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000449 cleanup_exit(255);
Damien Millere9264972002-09-30 11:59:21 +1000450 }
451
Damien Miller27dbe6f2001-03-19 22:36:20 +1100452 if (datafellows & SSH_BUG_SCANNER) {
Damien Miller996acd22003-04-09 20:59:48 +1000453 logit("scanned from %s with %s. Don't panic.",
Damien Miller27dbe6f2001-03-19 22:36:20 +1100454 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000455 cleanup_exit(255);
Damien Miller27dbe6f2001-03-19 22:36:20 +1100456 }
457
Damien Miller78928792000-04-12 20:17:38 +1000458 mismatch = 0;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000459 switch (remote_major) {
Damien Millerb38eff82000-04-01 11:09:21 +1000460 case 1:
Damien Millereba71ba2000-04-29 23:57:08 +1000461 if (remote_minor == 99) {
462 if (options.protocol & SSH_PROTO_2)
463 enable_compat20();
464 else
465 mismatch = 1;
466 break;
467 }
Damien Miller78928792000-04-12 20:17:38 +1000468 if (!(options.protocol & SSH_PROTO_1)) {
469 mismatch = 1;
470 break;
471 }
Damien Millerb38eff82000-04-01 11:09:21 +1000472 if (remote_minor < 3) {
Damien Miller37023962000-07-11 17:31:38 +1000473 packet_disconnect("Your ssh version is too old and "
Damien Millerb38eff82000-04-01 11:09:21 +1000474 "is no longer supported. Please install a newer version.");
475 } else if (remote_minor == 3) {
476 /* note that this disables agent-forwarding */
477 enable_compat13();
478 }
Damien Miller78928792000-04-12 20:17:38 +1000479 break;
Damien Millerefb4afe2000-04-12 18:45:05 +1000480 case 2:
Damien Miller78928792000-04-12 20:17:38 +1000481 if (options.protocol & SSH_PROTO_2) {
Damien Millerefb4afe2000-04-12 18:45:05 +1000482 enable_compat20();
483 break;
484 }
485 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000486 default:
Damien Miller78928792000-04-12 20:17:38 +1000487 mismatch = 1;
Damien Millerb38eff82000-04-01 11:09:21 +1000488 break;
489 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000490 chop(server_version_string);
Damien Miller78928792000-04-12 20:17:38 +1000491 debug("Local version string %.200s", server_version_string);
492
493 if (mismatch) {
494 s = "Protocol major versions differ.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000495 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Miller78928792000-04-12 20:17:38 +1000496 close(sock_in);
497 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000498 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
Damien Miller78928792000-04-12 20:17:38 +1000499 get_remote_ipaddr(),
500 server_version_string, client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000501 cleanup_exit(255);
Damien Miller78928792000-04-12 20:17:38 +1000502 }
Damien Millereba71ba2000-04-29 23:57:08 +1000503}
504
Damien Miller0bc1bd82000-11-13 22:57:25 +1100505/* Destroy the host and server keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +1000506void
507destroy_sensitive_data(void)
508{
Damien Miller0bc1bd82000-11-13 22:57:25 +1100509 int i;
510
511 if (sensitive_data.server_key) {
512 key_free(sensitive_data.server_key);
513 sensitive_data.server_key = NULL;
514 }
Damien Miller9f0f5c62001-12-21 14:45:46 +1100515 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100516 if (sensitive_data.host_keys[i]) {
517 key_free(sensitive_data.host_keys[i]);
518 sensitive_data.host_keys[i] = NULL;
519 }
520 }
521 sensitive_data.ssh1_host_key = NULL;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000522 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100523}
Damien Miller0bc1bd82000-11-13 22:57:25 +1100524
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000525/* Demote private to public keys for network child */
526void
527demote_sensitive_data(void)
528{
529 Key *tmp;
530 int i;
531
532 if (sensitive_data.server_key) {
533 tmp = key_demote(sensitive_data.server_key);
534 key_free(sensitive_data.server_key);
535 sensitive_data.server_key = tmp;
536 }
537
538 for (i = 0; i < options.num_host_key_files; i++) {
539 if (sensitive_data.host_keys[i]) {
540 tmp = key_demote(sensitive_data.host_keys[i]);
541 key_free(sensitive_data.host_keys[i]);
542 sensitive_data.host_keys[i] = tmp;
543 if (tmp->type == KEY_RSA1)
544 sensitive_data.ssh1_host_key = tmp;
545 }
546 }
547
548 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
549}
550
Ben Lindstrom08105192002-03-22 02:50:06 +0000551static void
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000552privsep_preauth_child(void)
553{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000554 u_int32_t rnd[256];
Ben Lindstrom810af962002-07-04 00:11:40 +0000555 gid_t gidset[1];
Ben Lindstromc7431342002-03-22 03:11:49 +0000556 struct passwd *pw;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000557 int i;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000558
559 /* Enable challenge-response authentication for privilege separation */
560 privsep_challenge_enable();
561
562 for (i = 0; i < 256; i++)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000563 rnd[i] = arc4random();
564 RAND_seed(rnd, sizeof(rnd));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000565
566 /* Demote the private keys to public keys. */
567 demote_sensitive_data();
568
Ben Lindstromc7431342002-03-22 03:11:49 +0000569 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
Damien Miller0150c652002-04-24 09:49:09 +1000570 fatal("Privilege separation user %s does not exist",
571 SSH_PRIVSEP_USER);
Ben Lindstromc7431342002-03-22 03:11:49 +0000572 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
573 endpwent();
574
Ben Lindstroma962c2f2002-07-04 00:14:17 +0000575 /* Change our root directory */
Ben Lindstrom7a7edf72002-03-22 02:42:37 +0000576 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
577 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
578 strerror(errno));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000579 if (chdir("/") == -1)
Ben Lindstrom1ee9ec32002-03-22 03:14:45 +0000580 fatal("chdir(\"/\"): %s", strerror(errno));
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000581
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000582 /* Drop our privileges */
Ben Lindstromc7431342002-03-22 03:11:49 +0000583 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
584 (u_int)pw->pw_gid);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000585#if 0
Darren Tuckerd5920482004-02-29 20:11:30 +1100586 /* XXX not ready, too heavy after chroot */
Ben Lindstromc7431342002-03-22 03:11:49 +0000587 do_setusercontext(pw);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000588#else
589 gidset[0] = pw->pw_gid;
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000590 if (setgroups(1, gidset) < 0)
591 fatal("setgroups: %.100s", strerror(errno));
592 permanently_set_uid(pw);
593#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000594}
595
Darren Tucker3e33cec2003-10-02 16:12:36 +1000596static int
597privsep_preauth(Authctxt *authctxt)
Ben Lindstrom943481c2002-03-22 03:43:46 +0000598{
Ben Lindstrom943481c2002-03-22 03:43:46 +0000599 int status;
600 pid_t pid;
601
602 /* Set up unprivileged child process to deal with network data */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000603 pmonitor = monitor_init();
Ben Lindstrom943481c2002-03-22 03:43:46 +0000604 /* Store a pointer to the kex for later rekeying */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000605 pmonitor->m_pkex = &xxx_kex;
Ben Lindstrom943481c2002-03-22 03:43:46 +0000606
607 pid = fork();
608 if (pid == -1) {
609 fatal("fork of unprivileged child failed");
610 } else if (pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000611 debug2("Network child is on pid %ld", (long)pid);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000612
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000613 close(pmonitor->m_recvfd);
Darren Tuckera8be9e22004-02-06 16:40:27 +1100614 pmonitor->m_pid = pid;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000615 monitor_child_preauth(authctxt, pmonitor);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000616 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000617
618 /* Sync memory */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000619 monitor_sync(pmonitor);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000620
621 /* Wait for the child's exit status */
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000622 while (waitpid(pid, &status, 0) < 0)
623 if (errno != EINTR)
624 break;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000625 return (1);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000626 } else {
627 /* child */
628
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000629 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000630
631 /* Demote the child */
632 if (getuid() == 0 || geteuid() == 0)
633 privsep_preauth_child();
Ben Lindstromf90f58d2002-03-26 01:53:03 +0000634 setproctitle("%s", "[net]");
Ben Lindstrom943481c2002-03-22 03:43:46 +0000635 }
Darren Tucker3e33cec2003-10-02 16:12:36 +1000636 return (0);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000637}
638
Ben Lindstrom08105192002-03-22 02:50:06 +0000639static void
Ben Lindstrom943481c2002-03-22 03:43:46 +0000640privsep_postauth(Authctxt *authctxt)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000641{
Tim Rice9dd30812002-07-07 13:43:36 -0700642#ifdef DISABLE_FD_PASSING
Tim Rice8eff3192002-06-25 15:35:15 -0700643 if (1) {
644#else
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000645 if (authctxt->pw->pw_uid == 0 || options.use_login) {
Tim Rice8eff3192002-06-25 15:35:15 -0700646#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000647 /* File descriptor passing is broken or root login */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000648 use_privsep = 0;
Darren Tucker45b01422005-10-03 18:20:00 +1000649 goto skip;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000650 }
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000651
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000652 /* New socket pair */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000653 monitor_reinit(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000654
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000655 pmonitor->m_pid = fork();
656 if (pmonitor->m_pid == -1)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000657 fatal("fork of unprivileged child failed");
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000658 else if (pmonitor->m_pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000659 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000660 close(pmonitor->m_recvfd);
Darren Tuckereb578622004-08-12 23:08:14 +1000661 buffer_clear(&loginmsg);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000662 monitor_child_postauth(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000663
664 /* NEVERREACHED */
665 exit(0);
666 }
667
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000668 close(pmonitor->m_sendfd);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000669
670 /* Demote the private keys to public keys. */
671 demote_sensitive_data();
672
673 /* Drop privileges */
674 do_setusercontext(authctxt->pw);
675
Darren Tucker45b01422005-10-03 18:20:00 +1000676 skip:
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000677 /* It is safe now to apply the key state */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000678 monitor_apply_keystate(pmonitor);
Damien Miller9786e6e2005-07-26 21:54:56 +1000679
680 /*
681 * Tell the packet layer that authentication was successful, since
682 * this information is not part of the key state.
683 */
684 packet_set_authenticated();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000685}
686
Ben Lindstrombba81212001-06-25 05:01:22 +0000687static char *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100688list_hostkey_types(void)
689{
Damien Miller0e3b8722002-01-22 23:26:38 +1100690 Buffer b;
Damien Millerf58b58c2003-11-17 21:18:23 +1100691 const char *p;
692 char *ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100693 int i;
Damien Miller0e3b8722002-01-22 23:26:38 +1100694
695 buffer_init(&b);
Damien Miller9f0f5c62001-12-21 14:45:46 +1100696 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100697 Key *key = sensitive_data.host_keys[i];
698 if (key == NULL)
699 continue;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000700 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100701 case KEY_RSA:
702 case KEY_DSA:
Damien Miller0e3b8722002-01-22 23:26:38 +1100703 if (buffer_len(&b) > 0)
704 buffer_append(&b, ",", 1);
705 p = key_ssh_name(key);
706 buffer_append(&b, p, strlen(p));
Damien Miller0bc1bd82000-11-13 22:57:25 +1100707 break;
708 }
709 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100710 buffer_append(&b, "\0", 1);
Damien Millerf58b58c2003-11-17 21:18:23 +1100711 ret = xstrdup(buffer_ptr(&b));
Damien Miller0e3b8722002-01-22 23:26:38 +1100712 buffer_free(&b);
Damien Millerf58b58c2003-11-17 21:18:23 +1100713 debug("list_hostkey_types: %s", ret);
714 return ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100715}
716
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000717Key *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100718get_hostkey_by_type(int type)
719{
720 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000721
Damien Miller9f0f5c62001-12-21 14:45:46 +1100722 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100723 Key *key = sensitive_data.host_keys[i];
724 if (key != NULL && key->type == type)
725 return key;
726 }
727 return NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000728}
729
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000730Key *
731get_hostkey_by_index(int ind)
732{
733 if (ind < 0 || ind >= options.num_host_key_files)
734 return (NULL);
735 return (sensitive_data.host_keys[ind]);
736}
737
738int
739get_hostkey_index(Key *key)
740{
741 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000742
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000743 for (i = 0; i < options.num_host_key_files; i++) {
744 if (key == sensitive_data.host_keys[i])
745 return (i);
746 }
747 return (-1);
748}
749
Damien Miller942da032000-08-18 13:59:06 +1000750/*
751 * returns 1 if connection should be dropped, 0 otherwise.
752 * dropping starts at connection #max_startups_begin with a probability
753 * of (max_startups_rate/100). the probability increases linearly until
754 * all connections are dropped for startups > max_startups
755 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000756static int
Damien Miller942da032000-08-18 13:59:06 +1000757drop_connection(int startups)
758{
Darren Tucker178fa662004-11-05 20:09:09 +1100759 int p, r;
Damien Miller942da032000-08-18 13:59:06 +1000760
761 if (startups < options.max_startups_begin)
762 return 0;
763 if (startups >= options.max_startups)
764 return 1;
765 if (options.max_startups_rate == 100)
766 return 1;
767
768 p = 100 - options.max_startups_rate;
769 p *= startups - options.max_startups_begin;
Darren Tucker178fa662004-11-05 20:09:09 +1100770 p /= options.max_startups - options.max_startups_begin;
Damien Miller942da032000-08-18 13:59:06 +1000771 p += options.max_startups_rate;
Darren Tucker178fa662004-11-05 20:09:09 +1100772 r = arc4random() % 100;
Damien Miller942da032000-08-18 13:59:06 +1000773
Darren Tucker3269b132004-11-05 20:20:59 +1100774 debug("drop_connection: p %d, r %d", p, r);
Damien Miller942da032000-08-18 13:59:06 +1000775 return (r < p) ? 1 : 0;
776}
777
Ben Lindstromade03f62001-12-06 18:22:17 +0000778static void
779usage(void)
780{
Damien Miller0c889cd2004-03-22 09:36:00 +1100781 fprintf(stderr, "%s, %s\n",
Damien Miller2aa6d3c2004-09-12 16:53:04 +1000782 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
Damien Millerb4087862004-03-22 09:35:21 +1100783 fprintf(stderr,
784"usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n"
785" [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n"
786 );
Ben Lindstromade03f62001-12-06 18:22:17 +0000787 exit(1);
788}
789
Darren Tucker645ab752004-06-25 13:33:20 +1000790static void
791send_rexec_state(int fd, Buffer *conf)
792{
793 Buffer m;
794
795 debug3("%s: entering fd = %d config len %d", __func__, fd,
796 buffer_len(conf));
797
798 /*
799 * Protocol from reexec master to child:
800 * string configuration
801 * u_int ephemeral_key_follows
802 * bignum e (only if ephemeral_key_follows == 1)
803 * bignum n "
804 * bignum d "
805 * bignum iqmp "
806 * bignum p "
807 * bignum q "
Darren Tuckerc6f82192005-09-27 22:46:32 +1000808 * string rngseed (only if OpenSSL is not self-seeded)
Darren Tucker645ab752004-06-25 13:33:20 +1000809 */
810 buffer_init(&m);
811 buffer_put_cstring(&m, buffer_ptr(conf));
812
Darren Tuckerfc959702004-07-17 16:12:08 +1000813 if (sensitive_data.server_key != NULL &&
Darren Tucker645ab752004-06-25 13:33:20 +1000814 sensitive_data.server_key->type == KEY_RSA1) {
815 buffer_put_int(&m, 1);
816 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
817 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
818 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
819 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
820 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
821 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
822 } else
823 buffer_put_int(&m, 0);
824
Darren Tuckerc6f82192005-09-27 22:46:32 +1000825#ifndef OPENSSL_PRNG_ONLY
826 rexec_send_rng_seed(&m);
827#endif
828
Darren Tucker645ab752004-06-25 13:33:20 +1000829 if (ssh_msg_send(fd, 0, &m) == -1)
830 fatal("%s: ssh_msg_send failed", __func__);
831
832 buffer_free(&m);
833
834 debug3("%s: done", __func__);
835}
836
837static void
838recv_rexec_state(int fd, Buffer *conf)
839{
840 Buffer m;
841 char *cp;
842 u_int len;
843
844 debug3("%s: entering fd = %d", __func__, fd);
845
846 buffer_init(&m);
847
848 if (ssh_msg_recv(fd, &m) == -1)
849 fatal("%s: ssh_msg_recv failed", __func__);
850 if (buffer_get_char(&m) != 0)
851 fatal("%s: rexec version mismatch", __func__);
852
853 cp = buffer_get_string(&m, &len);
854 if (conf != NULL)
855 buffer_append(conf, cp, len + 1);
856 xfree(cp);
857
858 if (buffer_get_int(&m)) {
859 if (sensitive_data.server_key != NULL)
860 key_free(sensitive_data.server_key);
861 sensitive_data.server_key = key_new_private(KEY_RSA1);
862 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
863 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
864 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
865 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
866 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
867 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
868 rsa_generate_additional_parameters(
869 sensitive_data.server_key->rsa);
870 }
Darren Tuckerc6f82192005-09-27 22:46:32 +1000871
872#ifndef OPENSSL_PRNG_ONLY
873 rexec_recv_rng_seed(&m);
874#endif
875
Darren Tucker645ab752004-06-25 13:33:20 +1000876 buffer_free(&m);
877
878 debug3("%s: done", __func__);
879}
880
Damien Miller95def091999-11-25 00:26:21 +1100881/*
882 * Main program for the daemon.
883 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000884int
885main(int ac, char **av)
886{
Damien Miller95def091999-11-25 00:26:21 +1100887 extern char *optarg;
888 extern int optind;
Damien Miller386c6a22004-06-30 22:40:20 +1000889 int opt, j, i, fdsetsz, on = 1;
890 int sock_in = -1, sock_out = -1, newsock = -1;
Damien Miller166fca82000-04-20 07:42:21 +1000891 pid_t pid;
Damien Miller34132e52000-01-14 15:45:46 +1100892 socklen_t fromlen;
Damien Miller34132e52000-01-14 15:45:46 +1100893 fd_set *fdset;
894 struct sockaddr_storage from;
Damien Miller95def091999-11-25 00:26:21 +1100895 const char *remote_ip;
896 int remote_port;
Damien Miller95def091999-11-25 00:26:21 +1100897 FILE *f;
Damien Miller34132e52000-01-14 15:45:46 +1100898 struct addrinfo *ai;
899 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
Damien Millerb9997192003-12-17 16:29:22 +1100900 char *line;
Damien Miller34132e52000-01-14 15:45:46 +1100901 int listen_sock, maxfd;
Darren Tucker0f56ed12004-08-29 16:38:41 +1000902 int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 };
Damien Miller37023962000-07-11 17:31:38 +1000903 int startups = 0;
Ben Lindstromd0fca422001-03-26 13:44:06 +0000904 Key *key;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000905 Authctxt *authctxt;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000906 int ret, key_used = 0;
Darren Tucker645ab752004-06-25 13:33:20 +1000907 Buffer cfg;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000908
Kevin Steves0ea1d9d2002-04-25 18:17:04 +0000909#ifdef HAVE_SECUREWARE
910 (void)set_auth_parameters(ac, av);
911#endif
Damien Miller59d3d5b2003-08-22 09:34:41 +1000912 __progname = ssh_get_progname(av[0]);
Damien Millerf9b625c2000-07-09 22:42:32 +1000913 init_rng();
914
Damien Millera8ed44b2003-01-10 09:53:12 +1100915 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
Damien Millerb8c656e2000-06-28 15:22:41 +1000916 saved_argc = ac;
Darren Tucker17c5d032004-06-25 14:22:23 +1000917 rexec_argc = ac;
Damien Miller04cb5362003-05-15 21:29:10 +1000918 saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1));
Damien Millera8ed44b2003-01-10 09:53:12 +1100919 for (i = 0; i < ac; i++)
920 saved_argv[i] = xstrdup(av[i]);
Damien Miller04cb5362003-05-15 21:29:10 +1000921 saved_argv[i] = NULL;
Damien Millera8ed44b2003-01-10 09:53:12 +1100922
923#ifndef HAVE_SETPROCTITLE
924 /* Prepare for later setproctitle emulation */
925 compat_init_setproctitle(ac, av);
Damien Millerf2e3e9d2003-06-02 12:15:54 +1000926 av = saved_argv;
Damien Millera8ed44b2003-01-10 09:53:12 +1100927#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000928
Damien Millerbfba3542004-03-22 09:29:57 +1100929 if (geteuid() == 0 && setgroups(0, NULL) == -1)
930 debug("setgroups(): %.200s", strerror(errno));
931
Darren Tuckerce321d82005-10-03 18:11:24 +1000932 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
933 sanitise_stdfd();
934
Damien Miller95def091999-11-25 00:26:21 +1100935 /* Initialize configuration options to their default values. */
936 initialize_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000937
Damien Miller95def091999-11-25 00:26:21 +1100938 /* Parse command-line arguments. */
Darren Tucker645ab752004-06-25 13:33:20 +1000939 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) {
Damien Miller95def091999-11-25 00:26:21 +1100940 switch (opt) {
Damien Miller34132e52000-01-14 15:45:46 +1100941 case '4':
Darren Tucker0f383232005-01-20 10:57:56 +1100942 options.address_family = AF_INET;
Damien Miller34132e52000-01-14 15:45:46 +1100943 break;
944 case '6':
Darren Tucker0f383232005-01-20 10:57:56 +1100945 options.address_family = AF_INET6;
Damien Miller34132e52000-01-14 15:45:46 +1100946 break;
Damien Miller95def091999-11-25 00:26:21 +1100947 case 'f':
948 config_file_name = optarg;
949 break;
950 case 'd':
Darren Tuckere98dfa32003-07-19 19:54:31 +1000951 if (debug_flag == 0) {
Damien Millere4340be2000-09-16 13:29:08 +1100952 debug_flag = 1;
953 options.log_level = SYSLOG_LEVEL_DEBUG1;
Darren Tuckere98dfa32003-07-19 19:54:31 +1000954 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
Damien Millere4340be2000-09-16 13:29:08 +1100955 options.log_level++;
Damien Miller95def091999-11-25 00:26:21 +1100956 break;
Ben Lindstromc72745a2000-12-02 19:03:54 +0000957 case 'D':
958 no_daemon_flag = 1;
959 break;
Ben Lindstrom9fce9f02001-04-11 23:10:09 +0000960 case 'e':
961 log_stderr = 1;
962 break;
Damien Miller95def091999-11-25 00:26:21 +1100963 case 'i':
964 inetd_flag = 1;
965 break;
Darren Tucker645ab752004-06-25 13:33:20 +1000966 case 'r':
967 rexec_flag = 0;
968 break;
969 case 'R':
970 rexeced_flag = 1;
971 inetd_flag = 1;
972 break;
Damien Miller95def091999-11-25 00:26:21 +1100973 case 'Q':
Ben Lindstromd5390202001-01-29 08:07:43 +0000974 /* ignored */
Damien Miller95def091999-11-25 00:26:21 +1100975 break;
976 case 'q':
977 options.log_level = SYSLOG_LEVEL_QUIET;
978 break;
979 case 'b':
980 options.server_key_bits = atoi(optarg);
981 break;
982 case 'p':
Damien Miller34132e52000-01-14 15:45:46 +1100983 options.ports_from_cmdline = 1;
Damien Millere4340be2000-09-16 13:29:08 +1100984 if (options.num_ports >= MAX_PORTS) {
985 fprintf(stderr, "too many ports.\n");
986 exit(1);
987 }
Ben Lindstrom19066a12001-04-12 23:39:26 +0000988 options.ports[options.num_ports++] = a2port(optarg);
989 if (options.ports[options.num_ports-1] == 0) {
990 fprintf(stderr, "Bad port number.\n");
991 exit(1);
992 }
Damien Miller95def091999-11-25 00:26:21 +1100993 break;
994 case 'g':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +0000995 if ((options.login_grace_time = convtime(optarg)) == -1) {
996 fprintf(stderr, "Invalid login grace time.\n");
997 exit(1);
998 }
Damien Miller95def091999-11-25 00:26:21 +1100999 break;
1000 case 'k':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +00001001 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
1002 fprintf(stderr, "Invalid key regeneration interval.\n");
1003 exit(1);
1004 }
Damien Miller95def091999-11-25 00:26:21 +11001005 break;
1006 case 'h':
Damien Miller0bc1bd82000-11-13 22:57:25 +11001007 if (options.num_host_key_files >= MAX_HOSTKEYS) {
1008 fprintf(stderr, "too many host keys.\n");
1009 exit(1);
1010 }
1011 options.host_key_files[options.num_host_key_files++] = optarg;
Damien Miller95def091999-11-25 00:26:21 +11001012 break;
Ben Lindstrom794325a2001-08-06 21:09:07 +00001013 case 't':
1014 test_flag = 1;
1015 break;
Damien Miller942da032000-08-18 13:59:06 +10001016 case 'u':
1017 utmp_len = atoi(optarg);
Ben Lindstrom41daec72002-07-23 21:15:13 +00001018 if (utmp_len > MAXHOSTNAMELEN) {
1019 fprintf(stderr, "Invalid utmp length.\n");
1020 exit(1);
1021 }
Damien Miller942da032000-08-18 13:59:06 +10001022 break;
Ben Lindstromade03f62001-12-06 18:22:17 +00001023 case 'o':
Damien Millerb9997192003-12-17 16:29:22 +11001024 line = xstrdup(optarg);
1025 if (process_server_config_line(&options, line,
Ben Lindstromade03f62001-12-06 18:22:17 +00001026 "command-line", 0) != 0)
Damien Miller9f0f5c62001-12-21 14:45:46 +11001027 exit(1);
Damien Millerb9997192003-12-17 16:29:22 +11001028 xfree(line);
Ben Lindstromade03f62001-12-06 18:22:17 +00001029 break;
Damien Miller95def091999-11-25 00:26:21 +11001030 case '?':
1031 default:
Ben Lindstromade03f62001-12-06 18:22:17 +00001032 usage();
1033 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001034 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001035 }
Darren Tucker645ab752004-06-25 13:33:20 +10001036 if (rexeced_flag || inetd_flag)
1037 rexec_flag = 0;
1038 if (rexec_flag && (av[0] == NULL || *av[0] != '/'))
1039 fatal("sshd re-exec requires execution with an absolute path");
1040 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001041 closefrom(REEXEC_MIN_FREE_FD);
1042 else
1043 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001044
Ben Lindstrom425fb022001-03-29 00:31:20 +00001045 SSLeay_add_all_algorithms();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001046
Damien Miller34132e52000-01-14 15:45:46 +11001047 /*
1048 * Force logging to stderr until we have loaded the private host
1049 * key (unless started from inetd)
1050 */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001051 log_init(__progname,
Damien Miller5aa5d782002-02-08 22:01:54 +11001052 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1053 SYSLOG_LEVEL_INFO : options.log_level,
1054 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1055 SYSLOG_FACILITY_AUTH : options.log_facility,
Ben Lindstromc2faa4a2002-11-09 15:50:03 +00001056 log_stderr || !inetd_flag);
Damien Miller34132e52000-01-14 15:45:46 +11001057
Darren Tucker86c093d2004-03-08 22:59:03 +11001058 /*
1059 * Unset KRB5CCNAME, otherwise the user's session may inherit it from
1060 * root's environment
Damien Miller94cf4c82005-07-17 17:04:47 +10001061 */
Darren Tucker9dc6c7d2005-02-02 18:30:33 +11001062 if (getenv("KRB5CCNAME") != NULL)
1063 unsetenv("KRB5CCNAME");
1064
Tim Rice81ed5182002-09-25 17:38:46 -07001065#ifdef _UNICOS
Darren Tucker12984962004-05-24 13:37:13 +10001066 /* Cray can define user privs drop all privs now!
Ben Lindstrom6db66ff2001-08-06 23:29:16 +00001067 * Not needed on PRIV_SU systems!
1068 */
1069 drop_cray_privs();
1070#endif
1071
Darren Tucker645ab752004-06-25 13:33:20 +10001072 sensitive_data.server_key = NULL;
1073 sensitive_data.ssh1_host_key = NULL;
1074 sensitive_data.have_ssh1_key = 0;
1075 sensitive_data.have_ssh2_key = 0;
1076
1077 /* Fetch our configuration */
1078 buffer_init(&cfg);
1079 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001080 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
Darren Tucker645ab752004-06-25 13:33:20 +10001081 else
1082 load_server_config(config_file_name, &cfg);
1083
1084 parse_server_config(&options,
1085 rexeced_flag ? "rexec" : config_file_name, &cfg);
1086
1087 if (!rexec_flag)
1088 buffer_free(&cfg);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001089
Darren Tuckerc6f82192005-09-27 22:46:32 +10001090 seed_rng();
1091
Damien Miller95def091999-11-25 00:26:21 +11001092 /* Fill in default values for those options not explicitly set. */
1093 fill_default_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001094
Darren Tucker0f383232005-01-20 10:57:56 +11001095 /* set default channel AF */
1096 channel_set_af(options.address_family);
1097
Damien Miller95def091999-11-25 00:26:21 +11001098 /* Check that there are no remaining arguments. */
1099 if (optind < ac) {
1100 fprintf(stderr, "Extra argument %s.\n", av[optind]);
1101 exit(1);
1102 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001103
Damien Miller2aa6d3c2004-09-12 16:53:04 +10001104 debug("sshd version %.100s", SSH_RELEASE);
Damien Miller2ccf6611999-11-15 15:25:10 +11001105
Damien Miller0bc1bd82000-11-13 22:57:25 +11001106 /* load private host keys */
Ben Lindstroma962c2f2002-07-04 00:14:17 +00001107 sensitive_data.host_keys = xmalloc(options.num_host_key_files *
1108 sizeof(Key *));
Damien Miller9f0f5c62001-12-21 14:45:46 +11001109 for (i = 0; i < options.num_host_key_files; i++)
Ben Lindstrom46c16222000-12-22 01:43:59 +00001110 sensitive_data.host_keys[i] = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +10001111
Damien Miller9f0f5c62001-12-21 14:45:46 +11001112 for (i = 0; i < options.num_host_key_files; i++) {
Ben Lindstromd0fca422001-03-26 13:44:06 +00001113 key = key_load_private(options.host_key_files[i], "", NULL);
1114 sensitive_data.host_keys[i] = key;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001115 if (key == NULL) {
Ben Lindstrom15f33862001-04-16 02:00:02 +00001116 error("Could not load host key: %s",
1117 options.host_key_files[i]);
Ben Lindstromd0fca422001-03-26 13:44:06 +00001118 sensitive_data.host_keys[i] = NULL;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001119 continue;
1120 }
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +00001121 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +11001122 case KEY_RSA1:
1123 sensitive_data.ssh1_host_key = key;
1124 sensitive_data.have_ssh1_key = 1;
1125 break;
1126 case KEY_RSA:
1127 case KEY_DSA:
1128 sensitive_data.have_ssh2_key = 1;
1129 break;
1130 }
Ben Lindstromd0fca422001-03-26 13:44:06 +00001131 debug("private host key: #%d type %d %s", i, key->type,
1132 key_type(key));
Damien Miller0bc1bd82000-11-13 22:57:25 +11001133 }
1134 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001135 logit("Disabling protocol version 1. Could not load host key");
Damien Millereba71ba2000-04-29 23:57:08 +10001136 options.protocol &= ~SSH_PROTO_1;
1137 }
Damien Miller0bc1bd82000-11-13 22:57:25 +11001138 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001139 logit("Disabling protocol version 2. Could not load host key");
Damien Miller0bc1bd82000-11-13 22:57:25 +11001140 options.protocol &= ~SSH_PROTO_2;
Damien Millereba71ba2000-04-29 23:57:08 +10001141 }
Kevin Stevesadf74cd2001-02-05 14:22:50 +00001142 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
Damien Miller996acd22003-04-09 20:59:48 +10001143 logit("sshd: no hostkeys available -- exiting.");
Damien Miller95def091999-11-25 00:26:21 +11001144 exit(1);
1145 }
Damien Miller95def091999-11-25 00:26:21 +11001146
Damien Millereba71ba2000-04-29 23:57:08 +10001147 /* Check certain values for sanity. */
1148 if (options.protocol & SSH_PROTO_1) {
1149 if (options.server_key_bits < 512 ||
1150 options.server_key_bits > 32768) {
1151 fprintf(stderr, "Bad server key size.\n");
1152 exit(1);
1153 }
1154 /*
1155 * Check that server and host key lengths differ sufficiently. This
1156 * is necessary to make double encryption work with rsaref. Oh, I
1157 * hate software patents. I dont know if this can go? Niels
1158 */
1159 if (options.server_key_bits >
Ben Lindstrom822b6342002-06-23 21:38:49 +00001160 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1161 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1162 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1163 SSH_KEY_BITS_RESERVED) {
Damien Millereba71ba2000-04-29 23:57:08 +10001164 options.server_key_bits =
Ben Lindstrom822b6342002-06-23 21:38:49 +00001165 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1166 SSH_KEY_BITS_RESERVED;
Damien Millereba71ba2000-04-29 23:57:08 +10001167 debug("Forcing server key to %d bits to make it differ from host key.",
1168 options.server_key_bits);
1169 }
1170 }
1171
Ben Lindstroma26ea632002-06-06 20:46:25 +00001172 if (use_privsep) {
1173 struct passwd *pw;
1174 struct stat st;
1175
1176 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1177 fatal("Privilege separation user %s does not exist",
1178 SSH_PRIVSEP_USER);
1179 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1180 (S_ISDIR(st.st_mode) == 0))
1181 fatal("Missing privilege separation directory: %s",
1182 _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstrom59627352002-06-27 18:02:21 +00001183
1184#ifdef HAVE_CYGWIN
1185 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1186 (st.st_uid != getuid () ||
1187 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1188#else
Ben Lindstrom2dfacb32002-06-23 00:33:47 +00001189 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
Ben Lindstrom59627352002-06-27 18:02:21 +00001190#endif
Damien Miller180fc5b2003-02-24 11:50:18 +11001191 fatal("%s must be owned by root and not group or "
1192 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstroma26ea632002-06-06 20:46:25 +00001193 }
1194
Ben Lindstrom794325a2001-08-06 21:09:07 +00001195 /* Configuration looks good, so exit if in test mode. */
1196 if (test_flag)
1197 exit(0);
1198
Damien Miller87aea252002-05-10 12:20:24 +10001199 /*
1200 * Clear out any supplemental groups we may have inherited. This
1201 * prevents inadvertent creation of files with bad modes (in the
Damien Millera8e06ce2003-11-21 23:48:55 +11001202 * portable version at least, it's certainly possible for PAM
1203 * to create a file, and we can't control the code in every
Damien Miller87aea252002-05-10 12:20:24 +10001204 * module which might be used).
1205 */
1206 if (setgroups(0, NULL) < 0)
1207 debug("setgroups() failed: %.200s", strerror(errno));
1208
Darren Tucker645ab752004-06-25 13:33:20 +10001209 if (rexec_flag) {
1210 rexec_argv = xmalloc(sizeof(char *) * (rexec_argc + 2));
1211 for (i = 0; i < rexec_argc; i++) {
1212 debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1213 rexec_argv[i] = saved_argv[i];
1214 }
1215 rexec_argv[rexec_argc] = "-R";
1216 rexec_argv[rexec_argc + 1] = NULL;
1217 }
1218
Damien Millereba71ba2000-04-29 23:57:08 +10001219 /* Initialize the log (it is reinitialized below in case we forked). */
Darren Tuckerea7c8122005-01-20 11:03:08 +11001220 if (debug_flag && (!inetd_flag || rexeced_flag))
Damien Miller95def091999-11-25 00:26:21 +11001221 log_stderr = 1;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001222 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001223
Damien Millereba71ba2000-04-29 23:57:08 +10001224 /*
1225 * If not in debugging mode, and not started from inetd, disconnect
1226 * from the controlling terminal, and fork. The original process
1227 * exits.
1228 */
Ben Lindstromc72745a2000-12-02 19:03:54 +00001229 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
Damien Miller95def091999-11-25 00:26:21 +11001230#ifdef TIOCNOTTY
1231 int fd;
1232#endif /* TIOCNOTTY */
1233 if (daemon(0, 0) < 0)
1234 fatal("daemon() failed: %.200s", strerror(errno));
1235
1236 /* Disconnect from the controlling tty. */
1237#ifdef TIOCNOTTY
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001238 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +11001239 if (fd >= 0) {
1240 (void) ioctl(fd, TIOCNOTTY, NULL);
1241 close(fd);
1242 }
1243#endif /* TIOCNOTTY */
1244 }
1245 /* Reinitialize the log (because of the fork above). */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001246 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001247
Damien Miller95def091999-11-25 00:26:21 +11001248 /* Initialize the random number generator. */
1249 arc4random_stir();
1250
1251 /* Chdir to the root directory so that the current disk can be
1252 unmounted if desired. */
1253 chdir("/");
Damien Miller9f0f5c62001-12-21 14:45:46 +11001254
Ben Lindstromde71cda2001-03-24 00:43:26 +00001255 /* ignore SIGPIPE */
1256 signal(SIGPIPE, SIG_IGN);
Damien Miller95def091999-11-25 00:26:21 +11001257
Damien Miller95def091999-11-25 00:26:21 +11001258 /* Start listening for a socket, unless started from inetd. */
1259 if (inetd_flag) {
Darren Tucker645ab752004-06-25 13:33:20 +10001260 int fd;
1261
Damien Miller994cf142000-07-21 10:19:44 +10001262 startup_pipe = -1;
Darren Tucker645ab752004-06-25 13:33:20 +10001263 if (rexeced_flag) {
Damien Miller035a5b42004-06-26 08:16:31 +10001264 close(REEXEC_CONFIG_PASS_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001265 sock_in = sock_out = dup(STDIN_FILENO);
1266 if (!debug_flag) {
Damien Miller035a5b42004-06-26 08:16:31 +10001267 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
1268 close(REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001269 }
1270 } else {
1271 sock_in = dup(STDIN_FILENO);
1272 sock_out = dup(STDOUT_FILENO);
1273 }
Damien Millereba71ba2000-04-29 23:57:08 +10001274 /*
1275 * We intentionally do not close the descriptors 0, 1, and 2
Darren Tucker645ab752004-06-25 13:33:20 +10001276 * as our code for setting the descriptors won't work if
Damien Millereba71ba2000-04-29 23:57:08 +10001277 * ttyfd happens to be one of those.
1278 */
Darren Tucker645ab752004-06-25 13:33:20 +10001279 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1280 dup2(fd, STDIN_FILENO);
1281 dup2(fd, STDOUT_FILENO);
1282 if (fd > STDOUT_FILENO)
1283 close(fd);
1284 }
Damien Miller95def091999-11-25 00:26:21 +11001285 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
Darren Tucker645ab752004-06-25 13:33:20 +10001286 if ((options.protocol & SSH_PROTO_1) &&
1287 sensitive_data.server_key == NULL)
Ben Lindstromca42d5f2001-03-09 18:25:32 +00001288 generate_ephemeral_server_key();
Damien Miller95def091999-11-25 00:26:21 +11001289 } else {
Damien Miller34132e52000-01-14 15:45:46 +11001290 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1291 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1292 continue;
1293 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1294 fatal("Too many listen sockets. "
1295 "Enlarge MAX_LISTEN_SOCKS");
Darren Tucker96d47102005-02-09 09:53:48 +11001296 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
Damien Miller34132e52000-01-14 15:45:46 +11001297 ntop, sizeof(ntop), strport, sizeof(strport),
Darren Tucker96d47102005-02-09 09:53:48 +11001298 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
1299 error("getnameinfo failed: %.100s",
1300 (ret != EAI_SYSTEM) ? gai_strerror(ret) :
1301 strerror(errno));
Damien Miller34132e52000-01-14 15:45:46 +11001302 continue;
1303 }
1304 /* Create socket for listening. */
Damien Miller2372ace2003-05-14 13:42:23 +10001305 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1306 ai->ai_protocol);
Damien Miller34132e52000-01-14 15:45:46 +11001307 if (listen_sock < 0) {
1308 /* kernel may not support ipv6 */
1309 verbose("socket: %.100s", strerror(errno));
1310 continue;
1311 }
Damien Miller232711f2004-06-15 10:35:30 +10001312 if (set_nonblock(listen_sock) == -1) {
Darren Tuckerefa37062004-02-24 09:20:29 +11001313 close(listen_sock);
1314 continue;
1315 }
Damien Miller34132e52000-01-14 15:45:46 +11001316 /*
Damien Millere1383ce2002-09-19 11:49:37 +10001317 * Set socket options.
1318 * Allow local port reuse in TIME_WAIT.
Damien Miller34132e52000-01-14 15:45:46 +11001319 */
Damien Millere1383ce2002-09-19 11:49:37 +10001320 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1321 &on, sizeof(on)) == -1)
1322 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +11001323
Damien Miller34132e52000-01-14 15:45:46 +11001324 debug("Bind to port %s on %s.", strport, ntop);
Damien Miller95def091999-11-25 00:26:21 +11001325
Damien Miller34132e52000-01-14 15:45:46 +11001326 /* Bind the socket to the desired port. */
Damien Miller0a4e27d2001-02-18 12:36:39 +11001327 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1328 if (!ai->ai_next)
1329 error("Bind to port %s on %s failed: %.200s.",
1330 strport, ntop, strerror(errno));
Damien Miller34132e52000-01-14 15:45:46 +11001331 close(listen_sock);
1332 continue;
1333 }
1334 listen_socks[num_listen_socks] = listen_sock;
1335 num_listen_socks++;
Damien Miller95def091999-11-25 00:26:21 +11001336
Damien Miller34132e52000-01-14 15:45:46 +11001337 /* Start listening on the port. */
Darren Tucker3175eb92003-12-09 19:15:11 +11001338 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
Damien Millerb24c2f82006-03-15 12:04:36 +11001339 fatal("listen on [%s]:%s: %.100s",
1340 ntop, strport, strerror(errno));
1341 logit("Server listening on %s port %s.", ntop, strport);
Damien Miller95def091999-11-25 00:26:21 +11001342 }
Damien Miller34132e52000-01-14 15:45:46 +11001343 freeaddrinfo(options.listen_addrs);
1344
1345 if (!num_listen_socks)
1346 fatal("Cannot bind any address.");
1347
Ben Lindstrom98097862001-06-25 05:10:20 +00001348 if (options.protocol & SSH_PROTO_1)
1349 generate_ephemeral_server_key();
1350
1351 /*
1352 * Arrange to restart on SIGHUP. The handler needs
1353 * listen_sock.
1354 */
1355 signal(SIGHUP, sighup_handler);
1356
1357 signal(SIGTERM, sigterm_handler);
1358 signal(SIGQUIT, sigterm_handler);
1359
1360 /* Arrange SIGCHLD to be caught. */
1361 signal(SIGCHLD, main_sigchld_handler);
1362
1363 /* Write out the pid file after the sigterm handler is setup */
Damien Miller95def091999-11-25 00:26:21 +11001364 if (!debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +11001365 /*
Ben Lindstrom7ad97102000-12-06 01:42:49 +00001366 * Record our pid in /var/run/sshd.pid to make it
1367 * easier to kill the correct sshd. We don't want to
1368 * do this before the bind above because the bind will
Damien Miller5428f641999-11-25 11:54:57 +11001369 * fail if there already is a daemon, and this will
1370 * overwrite any old pid in the file.
1371 */
Damien Millerbac2d8a2000-09-05 16:13:06 +11001372 f = fopen(options.pid_file, "wb");
Darren Tuckere5327042003-07-03 13:40:44 +10001373 if (f == NULL) {
1374 error("Couldn't create pid file \"%s\": %s",
1375 options.pid_file, strerror(errno));
1376 } else {
Ben Lindstromce0f6342002-06-11 16:42:49 +00001377 fprintf(f, "%ld\n", (long) getpid());
Damien Miller95def091999-11-25 00:26:21 +11001378 fclose(f);
1379 }
1380 }
Damien Miller95def091999-11-25 00:26:21 +11001381
Damien Miller34132e52000-01-14 15:45:46 +11001382 /* setup fd set for listen */
Damien Miller37023962000-07-11 17:31:38 +10001383 fdset = NULL;
Damien Miller34132e52000-01-14 15:45:46 +11001384 maxfd = 0;
1385 for (i = 0; i < num_listen_socks; i++)
1386 if (listen_socks[i] > maxfd)
1387 maxfd = listen_socks[i];
Damien Miller37023962000-07-11 17:31:38 +10001388 /* pipes connected to unauthenticated childs */
1389 startup_pipes = xmalloc(options.max_startups * sizeof(int));
1390 for (i = 0; i < options.max_startups; i++)
1391 startup_pipes[i] = -1;
Damien Miller34132e52000-01-14 15:45:46 +11001392
Damien Miller5428f641999-11-25 11:54:57 +11001393 /*
1394 * Stay listening for connections until the system crashes or
1395 * the daemon is killed with a signal.
1396 */
Damien Miller95def091999-11-25 00:26:21 +11001397 for (;;) {
1398 if (received_sighup)
1399 sighup_restart();
Damien Miller37023962000-07-11 17:31:38 +10001400 if (fdset != NULL)
1401 xfree(fdset);
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001402 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
Damien Miller37023962000-07-11 17:31:38 +10001403 fdset = (fd_set *)xmalloc(fdsetsz);
Damien Miller34132e52000-01-14 15:45:46 +11001404 memset(fdset, 0, fdsetsz);
Damien Miller37023962000-07-11 17:31:38 +10001405
Damien Miller34132e52000-01-14 15:45:46 +11001406 for (i = 0; i < num_listen_socks; i++)
1407 FD_SET(listen_socks[i], fdset);
Damien Miller37023962000-07-11 17:31:38 +10001408 for (i = 0; i < options.max_startups; i++)
1409 if (startup_pipes[i] != -1)
1410 FD_SET(startup_pipes[i], fdset);
1411
1412 /* Wait in select until there is a connection. */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001413 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1414 if (ret < 0 && errno != EINTR)
1415 error("select: %.100s", strerror(errno));
Ben Lindstromec46e0b2001-06-09 01:27:31 +00001416 if (received_sigterm) {
Damien Miller996acd22003-04-09 20:59:48 +10001417 logit("Received signal %d; terminating.",
Ben Lindstromf8f065b2001-12-06 17:52:16 +00001418 (int) received_sigterm);
Ben Lindstromec46e0b2001-06-09 01:27:31 +00001419 close_listen_socks();
1420 unlink(options.pid_file);
1421 exit(255);
1422 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001423 if (key_used && key_do_regen) {
Ben Lindstromca42d5f2001-03-09 18:25:32 +00001424 generate_ephemeral_server_key();
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001425 key_used = 0;
1426 key_do_regen = 0;
Damien Miller34132e52000-01-14 15:45:46 +11001427 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001428 if (ret < 0)
1429 continue;
1430
Damien Miller37023962000-07-11 17:31:38 +10001431 for (i = 0; i < options.max_startups; i++)
1432 if (startup_pipes[i] != -1 &&
1433 FD_ISSET(startup_pipes[i], fdset)) {
1434 /*
1435 * the read end of the pipe is ready
1436 * if the child has closed the pipe
Ben Lindstrom4dccfa52000-12-28 16:40:05 +00001437 * after successful authentication
Damien Miller37023962000-07-11 17:31:38 +10001438 * or if the child has died
1439 */
1440 close(startup_pipes[i]);
1441 startup_pipes[i] = -1;
1442 startups--;
1443 }
Damien Miller34132e52000-01-14 15:45:46 +11001444 for (i = 0; i < num_listen_socks; i++) {
1445 if (!FD_ISSET(listen_socks[i], fdset))
Damien Miller95def091999-11-25 00:26:21 +11001446 continue;
Damien Miller37023962000-07-11 17:31:38 +10001447 fromlen = sizeof(from);
1448 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1449 &fromlen);
1450 if (newsock < 0) {
1451 if (errno != EINTR && errno != EWOULDBLOCK)
1452 error("accept: %.100s", strerror(errno));
1453 continue;
1454 }
Damien Miller232711f2004-06-15 10:35:30 +10001455 if (unset_nonblock(newsock) == -1) {
Darren Tuckerefa37062004-02-24 09:20:29 +11001456 close(newsock);
1457 continue;
1458 }
Damien Miller942da032000-08-18 13:59:06 +10001459 if (drop_connection(startups) == 1) {
1460 debug("drop connection #%d", startups);
Damien Miller37023962000-07-11 17:31:38 +10001461 close(newsock);
1462 continue;
1463 }
1464 if (pipe(startup_p) == -1) {
1465 close(newsock);
1466 continue;
1467 }
1468
Darren Tucker645ab752004-06-25 13:33:20 +10001469 if (rexec_flag && socketpair(AF_UNIX,
1470 SOCK_STREAM, 0, config_s) == -1) {
1471 error("reexec socketpair: %s",
1472 strerror(errno));
1473 close(newsock);
1474 close(startup_p[0]);
1475 close(startup_p[1]);
1476 continue;
1477 }
1478
Damien Miller37023962000-07-11 17:31:38 +10001479 for (j = 0; j < options.max_startups; j++)
1480 if (startup_pipes[j] == -1) {
1481 startup_pipes[j] = startup_p[0];
1482 if (maxfd < startup_p[0])
1483 maxfd = startup_p[0];
1484 startups++;
1485 break;
1486 }
Kevin Stevesef4eea92001-02-05 12:42:17 +00001487
Damien Miller5428f641999-11-25 11:54:57 +11001488 /*
Damien Miller37023962000-07-11 17:31:38 +10001489 * Got connection. Fork a child to handle it, unless
1490 * we are in debugging mode.
Damien Miller5428f641999-11-25 11:54:57 +11001491 */
Damien Miller37023962000-07-11 17:31:38 +10001492 if (debug_flag) {
Damien Miller5428f641999-11-25 11:54:57 +11001493 /*
Damien Miller37023962000-07-11 17:31:38 +10001494 * In debugging mode. Close the listening
1495 * socket, and start processing the
1496 * connection without forking.
Damien Miller5428f641999-11-25 11:54:57 +11001497 */
Damien Miller37023962000-07-11 17:31:38 +10001498 debug("Server will not fork when running in debugging mode.");
Damien Miller34132e52000-01-14 15:45:46 +11001499 close_listen_socks();
Damien Miller95def091999-11-25 00:26:21 +11001500 sock_in = newsock;
1501 sock_out = newsock;
Darren Tucker645ab752004-06-25 13:33:20 +10001502 close(startup_p[0]);
1503 close(startup_p[1]);
Damien Miller4d97ba22000-07-11 18:15:50 +10001504 startup_pipe = -1;
Damien Miller182ee6e2000-07-12 09:45:27 +10001505 pid = getpid();
Darren Tucker645ab752004-06-25 13:33:20 +10001506 if (rexec_flag) {
1507 send_rexec_state(config_s[0],
1508 &cfg);
1509 close(config_s[0]);
1510 }
Damien Miller95def091999-11-25 00:26:21 +11001511 break;
Damien Miller37023962000-07-11 17:31:38 +10001512 } else {
1513 /*
1514 * Normal production daemon. Fork, and have
1515 * the child process the connection. The
1516 * parent continues listening.
1517 */
1518 if ((pid = fork()) == 0) {
1519 /*
1520 * Child. Close the listening and max_startup
1521 * sockets. Start using the accepted socket.
1522 * Reinitialize logging (since our pid has
1523 * changed). We break out of the loop to handle
1524 * the connection.
1525 */
1526 startup_pipe = startup_p[1];
Ben Lindstromd84df982001-12-06 16:35:40 +00001527 close_startup_pipes();
Damien Miller37023962000-07-11 17:31:38 +10001528 close_listen_socks();
1529 sock_in = newsock;
1530 sock_out = newsock;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001531 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Darren Tucker0f56ed12004-08-29 16:38:41 +10001532 if (rexec_flag)
1533 close(config_s[0]);
Damien Miller37023962000-07-11 17:31:38 +10001534 break;
1535 }
Damien Miller95def091999-11-25 00:26:21 +11001536 }
Damien Miller37023962000-07-11 17:31:38 +10001537
1538 /* Parent. Stay in the loop. */
1539 if (pid < 0)
1540 error("fork: %.100s", strerror(errno));
1541 else
Ben Lindstromce0f6342002-06-11 16:42:49 +00001542 debug("Forked child %ld.", (long)pid);
Damien Miller37023962000-07-11 17:31:38 +10001543
1544 close(startup_p[1]);
1545
Darren Tucker645ab752004-06-25 13:33:20 +10001546 if (rexec_flag) {
1547 send_rexec_state(config_s[0], &cfg);
1548 close(config_s[0]);
1549 close(config_s[1]);
1550 }
1551
Damien Miller37023962000-07-11 17:31:38 +10001552 /* Mark that the key has been used (it was "given" to the child). */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001553 if ((options.protocol & SSH_PROTO_1) &&
1554 key_used == 0) {
1555 /* Schedule server key regeneration alarm. */
Ben Lindstrom5ade9ab2003-08-25 01:16:21 +00001556 signal(SIGALRM, key_regeneration_alarm);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00001557 alarm(options.key_regeneration_time);
1558 key_used = 1;
1559 }
Damien Miller37023962000-07-11 17:31:38 +10001560
1561 arc4random_stir();
1562
1563 /* Close the new socket (the child is now taking care of it). */
1564 close(newsock);
Damien Miller95def091999-11-25 00:26:21 +11001565 }
Damien Miller34132e52000-01-14 15:45:46 +11001566 /* child process check (or debug mode) */
1567 if (num_listen_socks < 0)
1568 break;
Damien Miller95def091999-11-25 00:26:21 +11001569 }
1570 }
1571
1572 /* This is the child processing a new connection. */
Damien Miller57aae982004-03-08 23:11:25 +11001573 setproctitle("%s", "[accepted]");
Damien Miller95def091999-11-25 00:26:21 +11001574
Darren Tucker6832b832004-08-12 22:36:51 +10001575 /*
1576 * Create a new session and process group since the 4.4BSD
1577 * setlogin() affects the entire process group. We don't
1578 * want the child to be able to affect the parent.
1579 */
1580#if !defined(SSHD_ACQUIRES_CTTY)
1581 /*
1582 * If setsid is called, on some platforms sshd will later acquire a
1583 * controlling terminal which will result in "could not set
1584 * controlling tty" errors.
1585 */
1586 if (!debug_flag && !inetd_flag && setsid() < 0)
1587 error("setsid: %.100s", strerror(errno));
1588#endif
1589
Darren Tucker645ab752004-06-25 13:33:20 +10001590 if (rexec_flag) {
1591 int fd;
1592
Damien Miller035a5b42004-06-26 08:16:31 +10001593 debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1594 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001595 dup2(newsock, STDIN_FILENO);
1596 dup2(STDIN_FILENO, STDOUT_FILENO);
1597 if (startup_pipe == -1)
Damien Miller035a5b42004-06-26 08:16:31 +10001598 close(REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001599 else
Damien Miller035a5b42004-06-26 08:16:31 +10001600 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001601
Damien Miller035a5b42004-06-26 08:16:31 +10001602 dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001603 close(config_s[1]);
Darren Tuckerd8835932004-08-12 22:42:29 +10001604 if (startup_pipe != -1)
1605 close(startup_pipe);
Damien Miller035a5b42004-06-26 08:16:31 +10001606
Darren Tucker645ab752004-06-25 13:33:20 +10001607 execv(rexec_argv[0], rexec_argv);
1608
1609 /* Reexec has failed, fall back and continue */
1610 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
Damien Miller035a5b42004-06-26 08:16:31 +10001611 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
Darren Tucker645ab752004-06-25 13:33:20 +10001612 log_init(__progname, options.log_level,
1613 options.log_facility, log_stderr);
1614
1615 /* Clean up fds */
Damien Miller035a5b42004-06-26 08:16:31 +10001616 startup_pipe = REEXEC_STARTUP_PIPE_FD;
Darren Tucker645ab752004-06-25 13:33:20 +10001617 close(config_s[1]);
Damien Miller035a5b42004-06-26 08:16:31 +10001618 close(REEXEC_CONFIG_PASS_FD);
1619 newsock = sock_out = sock_in = dup(STDIN_FILENO);
Darren Tucker645ab752004-06-25 13:33:20 +10001620 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1621 dup2(fd, STDIN_FILENO);
1622 dup2(fd, STDOUT_FILENO);
1623 if (fd > STDERR_FILENO)
1624 close(fd);
1625 }
Damien Miller035a5b42004-06-26 08:16:31 +10001626 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1627 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001628 }
1629
Damien Miller5428f641999-11-25 11:54:57 +11001630 /*
1631 * Disable the key regeneration alarm. We will not regenerate the
1632 * key since we are no longer in a position to give it to anyone. We
1633 * will not restart on SIGHUP since it no longer makes sense.
1634 */
Damien Miller95def091999-11-25 00:26:21 +11001635 alarm(0);
1636 signal(SIGALRM, SIG_DFL);
1637 signal(SIGHUP, SIG_DFL);
1638 signal(SIGTERM, SIG_DFL);
1639 signal(SIGQUIT, SIG_DFL);
1640 signal(SIGCHLD, SIG_DFL);
Damien Miller4e0f5e12000-08-29 11:05:50 +11001641 signal(SIGINT, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +11001642
Damien Miller5428f641999-11-25 11:54:57 +11001643 /*
1644 * Register our connection. This turns encryption off because we do
1645 * not have a key.
1646 */
Damien Miller95def091999-11-25 00:26:21 +11001647 packet_set_connection(sock_in, sock_out);
Damien Miller9786e6e2005-07-26 21:54:56 +10001648 packet_set_server();
Damien Miller95def091999-11-25 00:26:21 +11001649
Damien Miller4f1d6b22005-05-26 11:59:32 +10001650 /* Set SO_KEEPALIVE if requested. */
1651 if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1652 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1653 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1654
Damien Miller677257f2005-06-17 12:55:03 +10001655 if ((remote_port = get_remote_port()) < 0) {
1656 debug("get_remote_port failed");
1657 cleanup_exit(255);
1658 }
Damien Miller4d3fd542005-11-05 15:13:24 +11001659
1660 /*
1661 * We use get_canonical_hostname with usedns = 0 instead of
1662 * get_remote_ipaddr here so IP options will be checked.
1663 */
1664 remote_ip = get_canonical_hostname(0);
Damien Miller95def091999-11-25 00:26:21 +11001665
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001666#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11001667 audit_connection_from(remote_ip, remote_port);
1668#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001669#ifdef LIBWRAP
Damien Miller6a4a4b92001-11-12 11:07:11 +11001670 /* Check whether logins are denied from this host. */
Darren Tucker586b0b92004-06-25 13:34:31 +10001671 if (packet_connection_is_on_socket()) {
Damien Miller95def091999-11-25 00:26:21 +11001672 struct request_info req;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001673
Ben Lindstromce89dac2001-09-12 16:58:04 +00001674 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
Damien Miller95def091999-11-25 00:26:21 +11001675 fromhost(&req);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001676
Damien Miller95def091999-11-25 00:26:21 +11001677 if (!hosts_access(&req)) {
Damien Miller6a4a4b92001-11-12 11:07:11 +11001678 debug("Connection refused by tcp wrapper");
Ben Lindstrom7de696e2001-03-29 00:45:12 +00001679 refuse(&req);
Damien Miller6a4a4b92001-11-12 11:07:11 +11001680 /* NOTREACHED */
1681 fatal("libwrap refuse returns");
Damien Miller95def091999-11-25 00:26:21 +11001682 }
Damien Miller95def091999-11-25 00:26:21 +11001683 }
Damien Miller34132e52000-01-14 15:45:46 +11001684#endif /* LIBWRAP */
Damien Miller6a4a4b92001-11-12 11:07:11 +11001685
Damien Miller95def091999-11-25 00:26:21 +11001686 /* Log the connection. */
1687 verbose("Connection from %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001688
Damien Miller5428f641999-11-25 11:54:57 +11001689 /*
Damien Miller788f2122005-11-05 15:14:59 +11001690 * We don't want to listen forever unless the other side
Damien Miller5428f641999-11-25 11:54:57 +11001691 * successfully authenticates itself. So we set up an alarm which is
1692 * cleared after successful authentication. A limit of zero
Damien Miller788f2122005-11-05 15:14:59 +11001693 * indicates no limit. Note that we don't set the alarm in debugging
Damien Miller5428f641999-11-25 11:54:57 +11001694 * mode; it is just annoying to have the server exit just when you
1695 * are about to discover the bug.
1696 */
Ben Lindstrom5ade9ab2003-08-25 01:16:21 +00001697 signal(SIGALRM, grace_alarm_handler);
Damien Miller95def091999-11-25 00:26:21 +11001698 if (!debug_flag)
1699 alarm(options.login_grace_time);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001700
Damien Millerb38eff82000-04-01 11:09:21 +10001701 sshd_exchange_identification(sock_in, sock_out);
Darren Tuckerec960f22003-08-13 20:37:05 +10001702
Damien Miller95def091999-11-25 00:26:21 +11001703 packet_set_nonblocking();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001704
Darren Tucker3e33cec2003-10-02 16:12:36 +10001705 /* allocate authentication context */
1706 authctxt = xmalloc(sizeof(*authctxt));
1707 memset(authctxt, 0, sizeof(*authctxt));
1708
Darren Tuckerf3bb4342005-03-31 21:39:25 +10001709 authctxt->loginmsg = &loginmsg;
1710
Darren Tucker3e33cec2003-10-02 16:12:36 +10001711 /* XXX global for cleanup, access from other modules */
1712 the_authctxt = authctxt;
1713
Darren Tucker5c14c732005-01-24 21:55:49 +11001714 /* prepare buffer to collect messages to display to user after login */
1715 buffer_init(&loginmsg);
1716
Ben Lindstrom943481c2002-03-22 03:43:46 +00001717 if (use_privsep)
Darren Tucker3e33cec2003-10-02 16:12:36 +10001718 if (privsep_preauth(authctxt) == 1)
Ben Lindstrom943481c2002-03-22 03:43:46 +00001719 goto authenticated;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001720
Damien Miller396691a2000-01-20 22:44:08 +11001721 /* perform the key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001722 /* authenticate user and start session */
Damien Millerefb4afe2000-04-12 18:45:05 +10001723 if (compat20) {
1724 do_ssh2_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001725 do_authentication2(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001726 } else {
1727 do_ssh1_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001728 do_authentication(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001729 }
Ben Lindstrom943481c2002-03-22 03:43:46 +00001730 /*
1731 * If we use privilege separation, the unprivileged child transfers
1732 * the current keystate and exits
1733 */
1734 if (use_privsep) {
Ben Lindstrom7339b2a2002-05-15 16:25:01 +00001735 mm_send_keystate(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001736 exit(0);
Ben Lindstrom943481c2002-03-22 03:43:46 +00001737 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001738
1739 authenticated:
Damien Miller7bff1a92005-12-24 14:59:12 +11001740 /*
1741 * Cancel the alarm we set to limit the time taken for
1742 * authentication.
1743 */
1744 alarm(0);
1745 signal(SIGALRM, SIG_DFL);
1746 if (startup_pipe != -1) {
1747 close(startup_pipe);
1748 startup_pipe = -1;
1749 }
1750
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001751#ifdef SSH_AUDIT_EVENTS
1752 audit_event(SSH_AUTH_SUCCESS);
Darren Tucker269a1ea2005-02-03 00:20:53 +11001753#endif
1754
Ben Lindstrom6328ab32002-03-22 02:54:23 +00001755 /*
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001756 * In privilege separation, we fork another child and prepare
1757 * file descriptor passing.
1758 */
1759 if (use_privsep) {
Ben Lindstrom943481c2002-03-22 03:43:46 +00001760 privsep_postauth(authctxt);
1761 /* the monitor process [priv] will not return */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001762 if (!compat20)
1763 destroy_sensitive_data();
1764 }
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001765
Darren Tucker3e33cec2003-10-02 16:12:36 +10001766 /* Start session. */
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001767 do_authenticated(authctxt);
1768
Damien Miller3a5b0232002-03-13 13:19:42 +11001769 /* The connection has been terminated. */
1770 verbose("Closing connection to %.100s", remote_ip);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001771
Damien Millerbeb4ba51999-12-28 15:09:35 +11001772#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +10001773 if (options.use_pam)
1774 finish_pam();
Damien Millerbeb4ba51999-12-28 15:09:35 +11001775#endif /* USE_PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001776
Darren Tucker2b59a6d2005-03-06 22:38:51 +11001777#ifdef SSH_AUDIT_EVENTS
1778 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE));
1779#endif
1780
Damien Miller95def091999-11-25 00:26:21 +11001781 packet_close();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001782
1783 if (use_privsep)
1784 mm_terminate();
1785
Damien Miller95def091999-11-25 00:26:21 +11001786 exit(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001787}
1788
Damien Miller95def091999-11-25 00:26:21 +11001789/*
Ben Lindstromabcb1452002-03-22 01:10:21 +00001790 * Decrypt session_key_int using our private server key and private host key
1791 * (key with larger modulus first).
1792 */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001793int
Ben Lindstromabcb1452002-03-22 01:10:21 +00001794ssh1_session_key(BIGNUM *session_key_int)
1795{
1796 int rsafail = 0;
1797
1798 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
1799 /* Server key has bigger modulus. */
1800 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1801 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1802 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1803 get_remote_ipaddr(),
1804 BN_num_bits(sensitive_data.server_key->rsa->n),
1805 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1806 SSH_KEY_BITS_RESERVED);
1807 }
1808 if (rsa_private_decrypt(session_key_int, session_key_int,
1809 sensitive_data.server_key->rsa) <= 0)
1810 rsafail++;
1811 if (rsa_private_decrypt(session_key_int, session_key_int,
1812 sensitive_data.ssh1_host_key->rsa) <= 0)
1813 rsafail++;
1814 } else {
1815 /* Host key has bigger modulus (or they are equal). */
1816 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1817 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1818 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1819 get_remote_ipaddr(),
1820 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1821 BN_num_bits(sensitive_data.server_key->rsa->n),
1822 SSH_KEY_BITS_RESERVED);
1823 }
1824 if (rsa_private_decrypt(session_key_int, session_key_int,
1825 sensitive_data.ssh1_host_key->rsa) < 0)
1826 rsafail++;
1827 if (rsa_private_decrypt(session_key_int, session_key_int,
1828 sensitive_data.server_key->rsa) < 0)
1829 rsafail++;
1830 }
1831 return (rsafail);
1832}
1833/*
Damien Miller396691a2000-01-20 22:44:08 +11001834 * SSH1 key exchange
Damien Miller95def091999-11-25 00:26:21 +11001835 */
Ben Lindstrombba81212001-06-25 05:01:22 +00001836static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001837do_ssh1_kex(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001838{
Damien Miller95def091999-11-25 00:26:21 +11001839 int i, len;
Damien Miller7650bc62001-01-30 09:27:26 +11001840 int rsafail = 0;
Damien Miller95def091999-11-25 00:26:21 +11001841 BIGNUM *session_key_int;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001842 u_char session_key[SSH_SESSION_KEY_LENGTH];
1843 u_char cookie[8];
1844 u_int cipher_type, auth_mask, protocol_flags;
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001845 u_int32_t rnd = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001846
Damien Miller5428f641999-11-25 11:54:57 +11001847 /*
1848 * Generate check bytes that the client must send back in the user
1849 * packet in order for it to be accepted; this is used to defy ip
1850 * spoofing attacks. Note that this only works against somebody
1851 * doing IP spoofing from a remote machine; any machine on the local
1852 * network can still see outgoing packets and catch the random
1853 * cookie. This only affects rhosts authentication, and this is one
1854 * of the reasons why it is inherently insecure.
1855 */
Damien Miller95def091999-11-25 00:26:21 +11001856 for (i = 0; i < 8; i++) {
1857 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001858 rnd = arc4random();
1859 cookie[i] = rnd & 0xff;
1860 rnd >>= 8;
Damien Miller95def091999-11-25 00:26:21 +11001861 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001862
Damien Miller5428f641999-11-25 11:54:57 +11001863 /*
1864 * Send our public key. We include in the packet 64 bits of random
1865 * data that must be matched in the reply in order to prevent IP
1866 * spoofing.
1867 */
Damien Miller95def091999-11-25 00:26:21 +11001868 packet_start(SSH_SMSG_PUBLIC_KEY);
1869 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001870 packet_put_char(cookie[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001871
Damien Miller95def091999-11-25 00:26:21 +11001872 /* Store our public server RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001873 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1874 packet_put_bignum(sensitive_data.server_key->rsa->e);
1875 packet_put_bignum(sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001876
Damien Miller95def091999-11-25 00:26:21 +11001877 /* Store our public host RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001878 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1879 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1880 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001881
Damien Miller95def091999-11-25 00:26:21 +11001882 /* Put protocol flags. */
1883 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001884
Damien Miller95def091999-11-25 00:26:21 +11001885 /* Declare which ciphers we support. */
Damien Miller874d77b2000-10-14 16:23:11 +11001886 packet_put_int(cipher_mask_ssh1(0));
Damien Miller95def091999-11-25 00:26:21 +11001887
1888 /* Declare supported authentication types. */
1889 auth_mask = 0;
Damien Miller95def091999-11-25 00:26:21 +11001890 if (options.rhosts_rsa_authentication)
1891 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1892 if (options.rsa_authentication)
1893 auth_mask |= 1 << SSH_AUTH_RSA;
Ben Lindstrom551ea372001-06-05 18:56:16 +00001894 if (options.challenge_response_authentication == 1)
Damien Miller95def091999-11-25 00:26:21 +11001895 auth_mask |= 1 << SSH_AUTH_TIS;
Damien Miller95def091999-11-25 00:26:21 +11001896 if (options.password_authentication)
1897 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1898 packet_put_int(auth_mask);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001899
Damien Miller95def091999-11-25 00:26:21 +11001900 /* Send the packet and wait for it to be sent. */
1901 packet_send();
1902 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001903
Damien Miller0bc1bd82000-11-13 22:57:25 +11001904 debug("Sent %d bit server key and %d bit host key.",
1905 BN_num_bits(sensitive_data.server_key->rsa->n),
1906 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001907
Damien Miller95def091999-11-25 00:26:21 +11001908 /* Read clients reply (cipher type and session key). */
Damien Millerdff50992002-01-22 23:16:32 +11001909 packet_read_expect(SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001910
Damien Miller50945fa1999-12-09 10:31:37 +11001911 /* Get cipher type and check whether we accept this. */
Damien Miller95def091999-11-25 00:26:21 +11001912 cipher_type = packet_get_char();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001913
Damien Miller874d77b2000-10-14 16:23:11 +11001914 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
Damien Miller50945fa1999-12-09 10:31:37 +11001915 packet_disconnect("Warning: client selects unsupported cipher.");
1916
Damien Miller95def091999-11-25 00:26:21 +11001917 /* Get check bytes from the packet. These must match those we
1918 sent earlier with the public key packet. */
1919 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001920 if (cookie[i] != packet_get_char())
Damien Miller95def091999-11-25 00:26:21 +11001921 packet_disconnect("IP Spoofing check bytes do not match.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001922
Damien Miller95def091999-11-25 00:26:21 +11001923 debug("Encryption type: %.200s", cipher_name(cipher_type));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001924
Damien Miller95def091999-11-25 00:26:21 +11001925 /* Get the encrypted integer. */
Damien Millerda755162002-01-22 23:09:22 +11001926 if ((session_key_int = BN_new()) == NULL)
1927 fatal("do_ssh1_kex: BN_new failed");
Damien Millerd432ccf2002-01-22 23:14:44 +11001928 packet_get_bignum(session_key_int);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001929
Damien Miller95def091999-11-25 00:26:21 +11001930 protocol_flags = packet_get_int();
1931 packet_set_protocol_flags(protocol_flags);
Damien Miller48b03fc2002-01-22 23:11:40 +11001932 packet_check_eom();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001933
Ben Lindstromabcb1452002-03-22 01:10:21 +00001934 /* Decrypt session_key_int using host/server keys */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001935 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1936
Damien Miller5428f641999-11-25 11:54:57 +11001937 /*
1938 * Extract session key from the decrypted integer. The key is in the
1939 * least significant 256 bits of the integer; the first byte of the
1940 * key is in the highest bits.
1941 */
Damien Miller7650bc62001-01-30 09:27:26 +11001942 if (!rsafail) {
1943 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1944 len = BN_num_bytes(session_key_int);
Damien Millereccb9de2005-06-17 12:59:34 +10001945 if (len < 0 || (u_int)len > sizeof(session_key)) {
Damien Miller7650bc62001-01-30 09:27:26 +11001946 error("do_connection: bad session key len from %s: "
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001947 "session_key_int %d > sizeof(session_key) %lu",
1948 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
Damien Miller7650bc62001-01-30 09:27:26 +11001949 rsafail++;
1950 } else {
1951 memset(session_key, 0, sizeof(session_key));
1952 BN_bn2bin(session_key_int,
1953 session_key + sizeof(session_key) - len);
Ben Lindstromeb648a72001-03-05 06:00:29 +00001954
Darren Tuckere14e0052004-05-13 16:30:44 +10001955 derive_ssh1_session_id(
Darren Tuckerfc959702004-07-17 16:12:08 +10001956 sensitive_data.ssh1_host_key->rsa->n,
Darren Tuckere14e0052004-05-13 16:30:44 +10001957 sensitive_data.server_key->rsa->n,
1958 cookie, session_id);
Ben Lindstromeb648a72001-03-05 06:00:29 +00001959 /*
1960 * Xor the first 16 bytes of the session key with the
1961 * session id.
1962 */
1963 for (i = 0; i < 16; i++)
1964 session_key[i] ^= session_id[i];
Damien Miller7650bc62001-01-30 09:27:26 +11001965 }
1966 }
1967 if (rsafail) {
Ben Lindstromeb648a72001-03-05 06:00:29 +00001968 int bytes = BN_num_bytes(session_key_int);
Ben Lindstrom13c5d3b2002-02-26 18:00:48 +00001969 u_char *buf = xmalloc(bytes);
Ben Lindstromeb648a72001-03-05 06:00:29 +00001970 MD5_CTX md;
1971
Damien Miller996acd22003-04-09 20:59:48 +10001972 logit("do_connection: generating a fake encryption key");
Ben Lindstromeb648a72001-03-05 06:00:29 +00001973 BN_bn2bin(session_key_int, buf);
1974 MD5_Init(&md);
1975 MD5_Update(&md, buf, bytes);
1976 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1977 MD5_Final(session_key, &md);
1978 MD5_Init(&md);
1979 MD5_Update(&md, session_key, 16);
1980 MD5_Update(&md, buf, bytes);
1981 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1982 MD5_Final(session_key + 16, &md);
1983 memset(buf, 0, bytes);
1984 xfree(buf);
Ben Lindstrom941ac822001-03-05 06:25:23 +00001985 for (i = 0; i < 16; i++)
1986 session_id[i] = session_key[i] ^ session_key[i + 16];
Damien Miller7650bc62001-01-30 09:27:26 +11001987 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001988 /* Destroy the private and public keys. No longer. */
Damien Miller3a5b0232002-03-13 13:19:42 +11001989 destroy_sensitive_data();
Ben Lindstromeb648a72001-03-05 06:00:29 +00001990
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001991 if (use_privsep)
1992 mm_ssh1_session_id(session_id);
1993
Damien Miller396691a2000-01-20 22:44:08 +11001994 /* Destroy the decrypted integer. It is no longer needed. */
1995 BN_clear_free(session_key_int);
1996
Damien Miller95def091999-11-25 00:26:21 +11001997 /* Set the session key. From this on all communications will be encrypted. */
1998 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001999
Damien Miller95def091999-11-25 00:26:21 +11002000 /* Destroy our copy of the session key. It is no longer needed. */
2001 memset(session_key, 0, sizeof(session_key));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002002
Damien Miller95def091999-11-25 00:26:21 +11002003 debug("Received session key; encryption turned on.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002004
Ben Lindstromf666fec2002-06-06 19:51:58 +00002005 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
Damien Miller95def091999-11-25 00:26:21 +11002006 packet_start(SSH_SMSG_SUCCESS);
2007 packet_send();
2008 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002009}
Damien Millerefb4afe2000-04-12 18:45:05 +10002010
2011/*
2012 * SSH2 key exchange: diffie-hellman-group1-sha1
2013 */
Ben Lindstrombba81212001-06-25 05:01:22 +00002014static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00002015do_ssh2_kex(void)
Damien Millerefb4afe2000-04-12 18:45:05 +10002016{
Damien Millerefb4afe2000-04-12 18:45:05 +10002017 Kex *kex;
Damien Millerefb4afe2000-04-12 18:45:05 +10002018
Damien Miller78928792000-04-12 20:17:38 +10002019 if (options.ciphers != NULL) {
Damien Miller4af51302000-04-16 11:18:38 +10002020 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
Damien Miller78928792000-04-12 20:17:38 +10002021 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
2022 }
Damien Millera0ff4662001-03-30 10:49:35 +10002023 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
2024 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
2025 myproposal[PROPOSAL_ENC_ALGS_STOC] =
2026 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
2027
Ben Lindstrom06b33aa2001-02-15 03:01:59 +00002028 if (options.macs != NULL) {
2029 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2030 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2031 }
Damien Miller9786e6e2005-07-26 21:54:56 +10002032 if (options.compression == COMP_NONE) {
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002033 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2034 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
Damien Miller9786e6e2005-07-26 21:54:56 +10002035 } else if (options.compression == COMP_DELAYED) {
2036 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2037 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002038 }
Damien Miller9786e6e2005-07-26 21:54:56 +10002039
Damien Miller0bc1bd82000-11-13 22:57:25 +11002040 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
2041
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002042 /* start key exchange */
Ben Lindstrom238abf62001-04-04 17:52:53 +00002043 kex = kex_setup(myproposal);
Damien Miller8e7fb332003-02-24 12:03:03 +11002044 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
Damien Millerf675fc42004-06-15 10:30:09 +10002045 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
Damien Miller8e7fb332003-02-24 12:03:03 +11002046 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
Damien Millera63128d2006-03-15 12:08:28 +11002047 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002048 kex->server = 1;
2049 kex->client_version_string=client_version_string;
2050 kex->server_version_string=server_version_string;
2051 kex->load_host_key=&get_hostkey_by_type;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002052 kex->host_key_index=&get_hostkey_index;
Damien Millerefb4afe2000-04-12 18:45:05 +10002053
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002054 xxx_kex = kex;
2055
Ben Lindstrombe2cc432001-04-04 23:46:07 +00002056 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
Damien Miller874d77b2000-10-14 16:23:11 +11002057
Ben Lindstrom2d90e002001-04-04 02:00:54 +00002058 session_id2 = kex->session_id;
2059 session_id2_len = kex->session_id_len;
2060
Damien Miller874d77b2000-10-14 16:23:11 +11002061#ifdef DEBUG_KEXDH
2062 /* send 1st encrypted/maced/compressed message */
2063 packet_start(SSH2_MSG_IGNORE);
2064 packet_put_cstring("markus");
2065 packet_send();
2066 packet_write_wait();
2067#endif
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002068 debug("KEX done");
Damien Millerefb4afe2000-04-12 18:45:05 +10002069}
Darren Tucker3e33cec2003-10-02 16:12:36 +10002070
2071/* server specific fatal cleanup */
2072void
2073cleanup_exit(int i)
2074{
2075 if (the_authctxt)
2076 do_cleanup(the_authctxt);
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002077#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11002078 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
2079 if (!use_privsep || mm_is_monitor())
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002080 audit_event(SSH_CONNECTION_ABANDON);
Darren Tucker269a1ea2005-02-03 00:20:53 +11002081#endif
Darren Tucker3e33cec2003-10-02 16:12:36 +10002082 _exit(i);
2083}