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Damien Miller3f8123c2006-08-19 00:32:46 +10001/* $OpenBSD: sshd.c,v 1.347 2006/08/18 09:15:20 markus Exp $ */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002/*
Damien Miller95def091999-11-25 00:26:21 +11003 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
Damien Millere4340be2000-09-16 13:29:08 +11006 * This program is the ssh daemon. It listens for connections from clients,
7 * and performs authentication, executes use commands or shell, and forwards
Damien Miller95def091999-11-25 00:26:21 +11008 * information to/from the application to the user client over an encrypted
Damien Millere4340be2000-09-16 13:29:08 +11009 * connection. This can also handle forwarding of X11, TCP/IP, and
10 * authentication agent connections.
Damien Millerefb4afe2000-04-12 18:45:05 +100011 *
Damien Millere4340be2000-09-16 13:29:08 +110012 * As far as I am concerned, the code I have written for this software
13 * can be used freely for any purpose. Any derived versions of this
14 * software must be clearly marked as such, and if the derived work is
15 * incompatible with the protocol description in the RFC file, it must be
16 * called by a name other than "ssh" or "Secure Shell".
17 *
18 * SSH2 implementation:
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000019 * Privilege Separation:
Damien Millere4340be2000-09-16 13:29:08 +110020 *
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000021 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
22 * Copyright (c) 2002 Niels Provos. All rights reserved.
Damien Millere4340be2000-09-16 13:29:08 +110023 *
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
26 * are met:
27 * 1. Redistributions of source code must retain the above copyright
28 * notice, this list of conditions and the following disclaimer.
29 * 2. Redistributions in binary form must reproduce the above copyright
30 * notice, this list of conditions and the following disclaimer in the
31 * documentation and/or other materials provided with the distribution.
32 *
33 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
34 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
36 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
37 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
39 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
40 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
41 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
42 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Miller95def091999-11-25 00:26:21 +110043 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100044
45#include "includes.h"
Damien Miller17e91c02006-03-15 11:28:34 +110046
Damien Miller9cf6d072006-03-15 11:29:24 +110047#include <sys/types.h>
Damien Millerd7834352006-08-05 12:39:39 +100048#include <sys/ioctl.h>
49#include <sys/socket.h>
Damien Millerf17883e2006-03-15 11:45:54 +110050#ifdef HAVE_SYS_STAT_H
51# include <sys/stat.h>
52#endif
Damien Miller9aec9192006-08-05 10:57:45 +100053#ifdef HAVE_SYS_TIME_H
54# include <sys/time.h>
55#endif
Damien Millerd7834352006-08-05 12:39:39 +100056#include "openbsd-compat/sys-tree.h"
Damien Miller9cf6d072006-03-15 11:29:24 +110057#include <sys/wait.h>
Damien Miller03e20032006-03-15 11:16:59 +110058
Darren Tucker39972492006-07-12 22:22:46 +100059#include <errno.h>
Damien Miller57cf6382006-07-10 21:13:46 +100060#include <fcntl.h>
Damien Millerb8fe89c2006-07-24 14:51:00 +100061#include <netdb.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110062#ifdef HAVE_PATHS_H
Damien Miller03e20032006-03-15 11:16:59 +110063#include <paths.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110064#endif
Damien Millera1738e42006-07-10 21:33:04 +100065#include <grp.h>
Damien Miller9f2abc42006-07-10 20:53:08 +100066#include <pwd.h>
Damien Miller6ff3cad2006-03-15 11:52:09 +110067#include <signal.h>
Damien Millera7a73ee2006-08-05 11:37:59 +100068#include <stdio.h>
Damien Millere7a1e5c2006-08-05 11:34:19 +100069#include <stdlib.h>
Damien Millere3476ed2006-07-24 14:13:33 +100070#include <string.h>
Damien Miller75bb6642006-08-05 14:07:20 +100071#include <unistd.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100072
Ben Lindstrom226cfa02001-01-22 05:34:40 +000073#include <openssl/dh.h>
74#include <openssl/bn.h>
Damien Miller6a47f302002-02-13 13:55:06 +110075#include <openssl/md5.h>
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000076#include <openssl/rand.h>
Kevin Steves0ea1d9d2002-04-25 18:17:04 +000077#ifdef HAVE_SECUREWARE
78#include <sys/security.h>
79#include <prot.h>
80#endif
Ben Lindstrom226cfa02001-01-22 05:34:40 +000081
Damien Millerd7834352006-08-05 12:39:39 +100082#include "xmalloc.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000083#include "ssh.h"
84#include "ssh1.h"
85#include "ssh2.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100086#include "rsa.h"
Ben Lindstromd95c09c2001-02-18 19:13:33 +000087#include "sshpty.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100088#include "packet.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000089#include "log.h"
Damien Millerd7834352006-08-05 12:39:39 +100090#include "buffer.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100091#include "servconf.h"
92#include "uidswap.h"
93#include "compat.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000094#include "cipher.h"
Damien Millerb38eff82000-04-01 11:09:21 +100095#include "key.h"
Damien Millerd7834352006-08-05 12:39:39 +100096#include "kex.h"
Damien Miller874d77b2000-10-14 16:23:11 +110097#include "dh.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100098#include "myproposal.h"
Damien Millereba71ba2000-04-29 23:57:08 +100099#include "authfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000100#include "pathnames.h"
101#include "atomicio.h"
102#include "canohost.h"
Damien Millerd7834352006-08-05 12:39:39 +1000103#include "hostfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000104#include "auth.h"
105#include "misc.h"
Darren Tucker645ab752004-06-25 13:33:20 +1000106#include "msg.h"
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +0000107#include "dispatch.h"
Ben Lindstrom1bae4042001-10-03 17:46:39 +0000108#include "channels.h"
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +0000109#include "session.h"
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000110#include "monitor_mm.h"
111#include "monitor.h"
Damien Millerd7834352006-08-05 12:39:39 +1000112#ifdef GSSAPI
113#include "ssh-gss.h"
114#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000115#include "monitor_wrap.h"
116#include "monitor_fdpass.h"
Damien Millerb7576772006-07-10 20:23:39 +1000117#include "version.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000118
119#ifdef LIBWRAP
120#include <tcpd.h>
121#include <syslog.h>
122int allow_severity = LOG_INFO;
123int deny_severity = LOG_WARNING;
124#endif /* LIBWRAP */
125
126#ifndef O_NOCTTY
127#define O_NOCTTY 0
128#endif
129
Damien Miller035a5b42004-06-26 08:16:31 +1000130/* Re-exec fds */
131#define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
132#define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
133#define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
134#define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
135
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000136extern char *__progname;
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000137
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000138/* Server configuration options. */
139ServerOptions options;
140
141/* Name of the server configuration file. */
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000142char *config_file_name = _PATH_SERVER_CONFIG_FILE;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000143
Damien Miller4af51302000-04-16 11:18:38 +1000144/*
Damien Miller95def091999-11-25 00:26:21 +1100145 * Debug mode flag. This can be set on the command line. If debug
146 * mode is enabled, extra debugging output will be sent to the system
147 * log, the daemon will not go to background, and will exit after processing
148 * the first connection.
149 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000150int debug_flag = 0;
151
Ben Lindstrom794325a2001-08-06 21:09:07 +0000152/* Flag indicating that the daemon should only test the configuration and keys. */
153int test_flag = 0;
154
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000155/* Flag indicating that the daemon is being started from inetd. */
156int inetd_flag = 0;
157
Ben Lindstromc72745a2000-12-02 19:03:54 +0000158/* Flag indicating that sshd should not detach and become a daemon. */
159int no_daemon_flag = 0;
160
Damien Miller5ce662a1999-11-11 17:57:39 +1100161/* debug goes to stderr unless inetd_flag is set */
162int log_stderr = 0;
163
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000164/* Saved arguments to main(). */
165char **saved_argv;
Damien Millerb8c656e2000-06-28 15:22:41 +1000166int saved_argc;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000167
Darren Tucker645ab752004-06-25 13:33:20 +1000168/* re-exec */
169int rexeced_flag = 0;
170int rexec_flag = 1;
171int rexec_argc = 0;
172char **rexec_argv;
173
Damien Miller5428f641999-11-25 11:54:57 +1100174/*
Damien Miller34132e52000-01-14 15:45:46 +1100175 * The sockets that the server is listening; this is used in the SIGHUP
176 * signal handler.
Damien Miller5428f641999-11-25 11:54:57 +1100177 */
Damien Miller34132e52000-01-14 15:45:46 +1100178#define MAX_LISTEN_SOCKS 16
179int listen_socks[MAX_LISTEN_SOCKS];
180int num_listen_socks = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000181
Damien Miller5428f641999-11-25 11:54:57 +1100182/*
183 * the client's version string, passed by sshd2 in compat mode. if != NULL,
184 * sshd will skip the version-number exchange
185 */
Damien Miller95def091999-11-25 00:26:21 +1100186char *client_version_string = NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000187char *server_version_string = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000188
Ben Lindstrom8ac91062001-04-04 17:57:54 +0000189/* for rekeying XXX fixme */
190Kex *xxx_kex;
191
Damien Miller5428f641999-11-25 11:54:57 +1100192/*
193 * Any really sensitive data in the application is contained in this
194 * structure. The idea is that this structure could be locked into memory so
195 * that the pages do not get written into swap. However, there are some
196 * problems. The private key contains BIGNUMs, and we do not (in principle)
197 * have access to the internals of them, and locking just the structure is
198 * not very useful. Currently, memory locking is not implemented.
199 */
Damien Miller95def091999-11-25 00:26:21 +1100200struct {
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000201 Key *server_key; /* ephemeral server key */
Damien Miller0bc1bd82000-11-13 22:57:25 +1100202 Key *ssh1_host_key; /* ssh1 host key */
203 Key **host_keys; /* all private host keys */
204 int have_ssh1_key;
205 int have_ssh2_key;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000206 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000207} sensitive_data;
208
Damien Miller5428f641999-11-25 11:54:57 +1100209/*
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000210 * Flag indicating whether the RSA server key needs to be regenerated.
211 * Is set in the SIGALRM handler and cleared when the key is regenerated.
Damien Miller5428f641999-11-25 11:54:57 +1100212 */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000213static volatile sig_atomic_t key_do_regen = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000214
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000215/* This is set to true when a signal is received. */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000216static volatile sig_atomic_t received_sighup = 0;
217static volatile sig_atomic_t received_sigterm = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000218
Damien Millerb38eff82000-04-01 11:09:21 +1000219/* session identifier, used by RSA-auth */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000220u_char session_id[16];
Damien Millerb38eff82000-04-01 11:09:21 +1000221
Damien Millereba71ba2000-04-29 23:57:08 +1000222/* same for ssh2 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000223u_char *session_id2 = NULL;
Darren Tucker502d3842003-06-28 12:38:01 +1000224u_int session_id2_len = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000225
Damien Miller942da032000-08-18 13:59:06 +1000226/* record remote hostname or ip */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000227u_int utmp_len = MAXHOSTNAMELEN;
Damien Miller942da032000-08-18 13:59:06 +1000228
Ben Lindstromd84df982001-12-06 16:35:40 +0000229/* options.max_startup sized array of fd ints */
230int *startup_pipes = NULL;
231int startup_pipe; /* in child */
232
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000233/* variables used for privilege separation */
Darren Tucker45150472006-07-12 22:34:17 +1000234int use_privsep = -1;
Darren Tuckera8be9e22004-02-06 16:40:27 +1100235struct monitor *pmonitor = NULL;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000236
Darren Tucker3e33cec2003-10-02 16:12:36 +1000237/* global authentication context */
238Authctxt *the_authctxt = NULL;
239
Darren Tucker45150472006-07-12 22:34:17 +1000240/* sshd_config buffer */
241Buffer cfg;
242
Darren Tucker09991742004-07-17 17:05:14 +1000243/* message to be displayed after login */
244Buffer loginmsg;
245
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000246/* Prototypes for various functions defined later in this file. */
Ben Lindstrombba81212001-06-25 05:01:22 +0000247void destroy_sensitive_data(void);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000248void demote_sensitive_data(void);
Damien Miller98c7ad62000-03-09 21:27:49 +1100249
Ben Lindstrombba81212001-06-25 05:01:22 +0000250static void do_ssh1_kex(void);
251static void do_ssh2_kex(void);
Damien Miller874d77b2000-10-14 16:23:11 +1100252
Damien Miller98c7ad62000-03-09 21:27:49 +1100253/*
Damien Miller34132e52000-01-14 15:45:46 +1100254 * Close all listening sockets
255 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000256static void
Damien Miller34132e52000-01-14 15:45:46 +1100257close_listen_socks(void)
258{
259 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000260
Damien Miller34132e52000-01-14 15:45:46 +1100261 for (i = 0; i < num_listen_socks; i++)
262 close(listen_socks[i]);
263 num_listen_socks = -1;
264}
265
Ben Lindstromd84df982001-12-06 16:35:40 +0000266static void
267close_startup_pipes(void)
268{
269 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000270
Ben Lindstromd84df982001-12-06 16:35:40 +0000271 if (startup_pipes)
272 for (i = 0; i < options.max_startups; i++)
273 if (startup_pipes[i] != -1)
274 close(startup_pipes[i]);
275}
276
Damien Miller34132e52000-01-14 15:45:46 +1100277/*
Damien Miller95def091999-11-25 00:26:21 +1100278 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
279 * the effect is to reread the configuration file (and to regenerate
280 * the server key).
281 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100282
283/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000284static void
Damien Miller95def091999-11-25 00:26:21 +1100285sighup_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000286{
Ben Lindstrom07958482001-12-06 16:19:01 +0000287 int save_errno = errno;
288
Damien Miller95def091999-11-25 00:26:21 +1100289 received_sighup = 1;
290 signal(SIGHUP, sighup_handler);
Ben Lindstrom07958482001-12-06 16:19:01 +0000291 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000292}
293
Damien Miller95def091999-11-25 00:26:21 +1100294/*
295 * Called from the main program after receiving SIGHUP.
296 * Restarts the server.
297 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000298static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000299sighup_restart(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000300{
Damien Miller996acd22003-04-09 20:59:48 +1000301 logit("Received SIGHUP; restarting.");
Damien Miller34132e52000-01-14 15:45:46 +1100302 close_listen_socks();
Ben Lindstromd84df982001-12-06 16:35:40 +0000303 close_startup_pipes();
Damien Miller95def091999-11-25 00:26:21 +1100304 execv(saved_argv[0], saved_argv);
Damien Miller996acd22003-04-09 20:59:48 +1000305 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
Ben Lindstrom822b6342002-06-23 21:38:49 +0000306 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100307 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000308}
309
Damien Miller95def091999-11-25 00:26:21 +1100310/*
311 * Generic signal handler for terminating signals in the master daemon.
Damien Miller95def091999-11-25 00:26:21 +1100312 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100313/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000314static void
Damien Miller95def091999-11-25 00:26:21 +1100315sigterm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000316{
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000317 received_sigterm = sig;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000318}
319
Damien Miller95def091999-11-25 00:26:21 +1100320/*
321 * SIGCHLD handler. This is called whenever a child dies. This will then
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000322 * reap any zombies left by exited children.
Damien Miller95def091999-11-25 00:26:21 +1100323 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100324/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000325static void
Damien Miller95def091999-11-25 00:26:21 +1100326main_sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000327{
Damien Miller95def091999-11-25 00:26:21 +1100328 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000329 pid_t pid;
Damien Miller95def091999-11-25 00:26:21 +1100330 int status;
Damien Miller431f66b1999-11-21 18:31:57 +1100331
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000332 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
333 (pid < 0 && errno == EINTR))
Damien Miller95def091999-11-25 00:26:21 +1100334 ;
Damien Miller431f66b1999-11-21 18:31:57 +1100335
Damien Miller95def091999-11-25 00:26:21 +1100336 signal(SIGCHLD, main_sigchld_handler);
337 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000338}
339
Damien Miller95def091999-11-25 00:26:21 +1100340/*
341 * Signal handler for the alarm after the login grace period has expired.
342 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100343/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000344static void
Damien Miller95def091999-11-25 00:26:21 +1100345grace_alarm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000346{
Darren Tuckera8be9e22004-02-06 16:40:27 +1100347 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
348 kill(pmonitor->m_pid, SIGALRM);
349
Damien Miller95def091999-11-25 00:26:21 +1100350 /* Log error and exit. */
Damien Miller99a648e2006-08-19 00:32:20 +1000351 sigdie("Timeout before authentication for %s", get_remote_ipaddr());
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000352}
353
Damien Miller95def091999-11-25 00:26:21 +1100354/*
Damien Miller95def091999-11-25 00:26:21 +1100355 * Signal handler for the key regeneration alarm. Note that this
356 * alarm only occurs in the daemon waiting for connections, and it does not
357 * do anything with the private key or random state before forking.
358 * Thus there should be no concurrency control/asynchronous execution
359 * problems.
360 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000361static void
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000362generate_ephemeral_server_key(void)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100363{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000364 u_int32_t rnd = 0;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000365 int i;
366
Ben Lindstroma3700052001-04-05 23:26:32 +0000367 verbose("Generating %s%d bit RSA key.",
Damien Millerff75ac42001-03-30 10:50:32 +1000368 sensitive_data.server_key ? "new " : "", options.server_key_bits);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100369 if (sensitive_data.server_key != NULL)
370 key_free(sensitive_data.server_key);
Ben Lindstroma3700052001-04-05 23:26:32 +0000371 sensitive_data.server_key = key_generate(KEY_RSA1,
Damien Millerff75ac42001-03-30 10:50:32 +1000372 options.server_key_bits);
373 verbose("RSA key generation complete.");
Ben Lindstromeb648a72001-03-05 06:00:29 +0000374
375 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
376 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000377 rnd = arc4random();
378 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
379 rnd >>= 8;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000380 }
381 arc4random_stir();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100382}
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000383
Damien Millerf0b15df2006-03-26 13:59:20 +1100384/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000385static void
Damien Miller95def091999-11-25 00:26:21 +1100386key_regeneration_alarm(int sig)
387{
388 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000389
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000390 signal(SIGALRM, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +1100391 errno = save_errno;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000392 key_do_regen = 1;
Damien Miller95def091999-11-25 00:26:21 +1100393}
394
Ben Lindstrombba81212001-06-25 05:01:22 +0000395static void
Damien Millerb38eff82000-04-01 11:09:21 +1000396sshd_exchange_identification(int sock_in, int sock_out)
397{
Damien Millereccb9de2005-06-17 12:59:34 +1000398 u_int i;
399 int mismatch;
Damien Millerb38eff82000-04-01 11:09:21 +1000400 int remote_major, remote_minor;
Damien Miller78928792000-04-12 20:17:38 +1000401 int major, minor;
Damien Millerb38eff82000-04-01 11:09:21 +1000402 char *s;
403 char buf[256]; /* Must not be larger than remote_version. */
404 char remote_version[256]; /* Must be at least as big as buf. */
405
Damien Miller78928792000-04-12 20:17:38 +1000406 if ((options.protocol & SSH_PROTO_1) &&
407 (options.protocol & SSH_PROTO_2)) {
408 major = PROTOCOL_MAJOR_1;
409 minor = 99;
410 } else if (options.protocol & SSH_PROTO_2) {
411 major = PROTOCOL_MAJOR_2;
412 minor = PROTOCOL_MINOR_2;
413 } else {
414 major = PROTOCOL_MAJOR_1;
415 minor = PROTOCOL_MINOR_1;
416 }
417 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
Damien Millerb38eff82000-04-01 11:09:21 +1000418 server_version_string = xstrdup(buf);
419
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000420 /* Send our protocol version identification. */
421 if (atomicio(vwrite, sock_out, server_version_string,
422 strlen(server_version_string))
423 != strlen(server_version_string)) {
424 logit("Could not write ident string to %s", get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000425 cleanup_exit(255);
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000426 }
427
428 /* Read other sides version identification. */
429 memset(buf, 0, sizeof(buf));
430 for (i = 0; i < sizeof(buf) - 1; i++) {
431 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
432 logit("Did not receive identification string from %s",
433 get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000434 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000435 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000436 if (buf[i] == '\r') {
437 buf[i] = 0;
438 /* Kludge for F-Secure Macintosh < 1.0.2 */
439 if (i == 12 &&
440 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
Damien Millerb38eff82000-04-01 11:09:21 +1000441 break;
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000442 continue;
Damien Millerb38eff82000-04-01 11:09:21 +1000443 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000444 if (buf[i] == '\n') {
445 buf[i] = 0;
446 break;
447 }
Damien Millerb38eff82000-04-01 11:09:21 +1000448 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000449 buf[sizeof(buf) - 1] = 0;
450 client_version_string = xstrdup(buf);
Damien Millerb38eff82000-04-01 11:09:21 +1000451
452 /*
453 * Check that the versions match. In future this might accept
454 * several versions and set appropriate flags to handle them.
455 */
456 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
457 &remote_major, &remote_minor, remote_version) != 3) {
Damien Miller4af51302000-04-16 11:18:38 +1000458 s = "Protocol mismatch.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000459 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Millerb38eff82000-04-01 11:09:21 +1000460 close(sock_in);
461 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000462 logit("Bad protocol version identification '%.100s' from %s",
Damien Millerb38eff82000-04-01 11:09:21 +1000463 client_version_string, get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000464 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000465 }
466 debug("Client protocol version %d.%d; client software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100467 remote_major, remote_minor, remote_version);
Damien Millerb38eff82000-04-01 11:09:21 +1000468
Damien Millerefb4afe2000-04-12 18:45:05 +1000469 compat_datafellows(remote_version);
470
Damien Millere9264972002-09-30 11:59:21 +1000471 if (datafellows & SSH_BUG_PROBE) {
Damien Miller996acd22003-04-09 20:59:48 +1000472 logit("probed from %s with %s. Don't panic.",
Damien Millere9264972002-09-30 11:59:21 +1000473 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000474 cleanup_exit(255);
Damien Millere9264972002-09-30 11:59:21 +1000475 }
476
Damien Miller27dbe6f2001-03-19 22:36:20 +1100477 if (datafellows & SSH_BUG_SCANNER) {
Damien Miller996acd22003-04-09 20:59:48 +1000478 logit("scanned from %s with %s. Don't panic.",
Damien Miller27dbe6f2001-03-19 22:36:20 +1100479 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000480 cleanup_exit(255);
Damien Miller27dbe6f2001-03-19 22:36:20 +1100481 }
482
Damien Miller78928792000-04-12 20:17:38 +1000483 mismatch = 0;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000484 switch (remote_major) {
Damien Millerb38eff82000-04-01 11:09:21 +1000485 case 1:
Damien Millereba71ba2000-04-29 23:57:08 +1000486 if (remote_minor == 99) {
487 if (options.protocol & SSH_PROTO_2)
488 enable_compat20();
489 else
490 mismatch = 1;
491 break;
492 }
Damien Miller78928792000-04-12 20:17:38 +1000493 if (!(options.protocol & SSH_PROTO_1)) {
494 mismatch = 1;
495 break;
496 }
Damien Millerb38eff82000-04-01 11:09:21 +1000497 if (remote_minor < 3) {
Damien Miller37023962000-07-11 17:31:38 +1000498 packet_disconnect("Your ssh version is too old and "
Damien Millerb38eff82000-04-01 11:09:21 +1000499 "is no longer supported. Please install a newer version.");
500 } else if (remote_minor == 3) {
501 /* note that this disables agent-forwarding */
502 enable_compat13();
503 }
Damien Miller78928792000-04-12 20:17:38 +1000504 break;
Damien Millerefb4afe2000-04-12 18:45:05 +1000505 case 2:
Damien Miller78928792000-04-12 20:17:38 +1000506 if (options.protocol & SSH_PROTO_2) {
Damien Millerefb4afe2000-04-12 18:45:05 +1000507 enable_compat20();
508 break;
509 }
510 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000511 default:
Damien Miller78928792000-04-12 20:17:38 +1000512 mismatch = 1;
Damien Millerb38eff82000-04-01 11:09:21 +1000513 break;
514 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000515 chop(server_version_string);
Damien Miller78928792000-04-12 20:17:38 +1000516 debug("Local version string %.200s", server_version_string);
517
518 if (mismatch) {
519 s = "Protocol major versions differ.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000520 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Miller78928792000-04-12 20:17:38 +1000521 close(sock_in);
522 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000523 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
Damien Miller78928792000-04-12 20:17:38 +1000524 get_remote_ipaddr(),
525 server_version_string, client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000526 cleanup_exit(255);
Damien Miller78928792000-04-12 20:17:38 +1000527 }
Damien Millereba71ba2000-04-29 23:57:08 +1000528}
529
Damien Miller0bc1bd82000-11-13 22:57:25 +1100530/* Destroy the host and server keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +1000531void
532destroy_sensitive_data(void)
533{
Damien Miller0bc1bd82000-11-13 22:57:25 +1100534 int i;
535
536 if (sensitive_data.server_key) {
537 key_free(sensitive_data.server_key);
538 sensitive_data.server_key = NULL;
539 }
Damien Miller9f0f5c62001-12-21 14:45:46 +1100540 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100541 if (sensitive_data.host_keys[i]) {
542 key_free(sensitive_data.host_keys[i]);
543 sensitive_data.host_keys[i] = NULL;
544 }
545 }
546 sensitive_data.ssh1_host_key = NULL;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000547 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100548}
Damien Miller0bc1bd82000-11-13 22:57:25 +1100549
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000550/* Demote private to public keys for network child */
551void
552demote_sensitive_data(void)
553{
554 Key *tmp;
555 int i;
556
557 if (sensitive_data.server_key) {
558 tmp = key_demote(sensitive_data.server_key);
559 key_free(sensitive_data.server_key);
560 sensitive_data.server_key = tmp;
561 }
562
563 for (i = 0; i < options.num_host_key_files; i++) {
564 if (sensitive_data.host_keys[i]) {
565 tmp = key_demote(sensitive_data.host_keys[i]);
566 key_free(sensitive_data.host_keys[i]);
567 sensitive_data.host_keys[i] = tmp;
568 if (tmp->type == KEY_RSA1)
569 sensitive_data.ssh1_host_key = tmp;
570 }
571 }
572
573 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
574}
575
Ben Lindstrom08105192002-03-22 02:50:06 +0000576static void
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000577privsep_preauth_child(void)
578{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000579 u_int32_t rnd[256];
Ben Lindstrom810af962002-07-04 00:11:40 +0000580 gid_t gidset[1];
Ben Lindstromc7431342002-03-22 03:11:49 +0000581 struct passwd *pw;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000582 int i;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000583
584 /* Enable challenge-response authentication for privilege separation */
585 privsep_challenge_enable();
586
587 for (i = 0; i < 256; i++)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000588 rnd[i] = arc4random();
589 RAND_seed(rnd, sizeof(rnd));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000590
591 /* Demote the private keys to public keys. */
592 demote_sensitive_data();
593
Ben Lindstromc7431342002-03-22 03:11:49 +0000594 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
Damien Miller0150c652002-04-24 09:49:09 +1000595 fatal("Privilege separation user %s does not exist",
596 SSH_PRIVSEP_USER);
Ben Lindstromc7431342002-03-22 03:11:49 +0000597 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
598 endpwent();
599
Ben Lindstroma962c2f2002-07-04 00:14:17 +0000600 /* Change our root directory */
Ben Lindstrom7a7edf72002-03-22 02:42:37 +0000601 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
602 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
603 strerror(errno));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000604 if (chdir("/") == -1)
Ben Lindstrom1ee9ec32002-03-22 03:14:45 +0000605 fatal("chdir(\"/\"): %s", strerror(errno));
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000606
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000607 /* Drop our privileges */
Ben Lindstromc7431342002-03-22 03:11:49 +0000608 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
609 (u_int)pw->pw_gid);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000610#if 0
Darren Tuckerd5920482004-02-29 20:11:30 +1100611 /* XXX not ready, too heavy after chroot */
Ben Lindstromc7431342002-03-22 03:11:49 +0000612 do_setusercontext(pw);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000613#else
614 gidset[0] = pw->pw_gid;
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000615 if (setgroups(1, gidset) < 0)
616 fatal("setgroups: %.100s", strerror(errno));
617 permanently_set_uid(pw);
618#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000619}
620
Darren Tucker3e33cec2003-10-02 16:12:36 +1000621static int
622privsep_preauth(Authctxt *authctxt)
Ben Lindstrom943481c2002-03-22 03:43:46 +0000623{
Ben Lindstrom943481c2002-03-22 03:43:46 +0000624 int status;
625 pid_t pid;
626
627 /* Set up unprivileged child process to deal with network data */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000628 pmonitor = monitor_init();
Ben Lindstrom943481c2002-03-22 03:43:46 +0000629 /* Store a pointer to the kex for later rekeying */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000630 pmonitor->m_pkex = &xxx_kex;
Ben Lindstrom943481c2002-03-22 03:43:46 +0000631
632 pid = fork();
633 if (pid == -1) {
634 fatal("fork of unprivileged child failed");
635 } else if (pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000636 debug2("Network child is on pid %ld", (long)pid);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000637
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000638 close(pmonitor->m_recvfd);
Darren Tuckera8be9e22004-02-06 16:40:27 +1100639 pmonitor->m_pid = pid;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000640 monitor_child_preauth(authctxt, pmonitor);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000641 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000642
643 /* Sync memory */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000644 monitor_sync(pmonitor);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000645
646 /* Wait for the child's exit status */
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000647 while (waitpid(pid, &status, 0) < 0)
648 if (errno != EINTR)
649 break;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000650 return (1);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000651 } else {
652 /* child */
653
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000654 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000655
656 /* Demote the child */
657 if (getuid() == 0 || geteuid() == 0)
658 privsep_preauth_child();
Ben Lindstromf90f58d2002-03-26 01:53:03 +0000659 setproctitle("%s", "[net]");
Ben Lindstrom943481c2002-03-22 03:43:46 +0000660 }
Darren Tucker3e33cec2003-10-02 16:12:36 +1000661 return (0);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000662}
663
Ben Lindstrom08105192002-03-22 02:50:06 +0000664static void
Ben Lindstrom943481c2002-03-22 03:43:46 +0000665privsep_postauth(Authctxt *authctxt)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000666{
Tim Rice9dd30812002-07-07 13:43:36 -0700667#ifdef DISABLE_FD_PASSING
Tim Rice8eff3192002-06-25 15:35:15 -0700668 if (1) {
669#else
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000670 if (authctxt->pw->pw_uid == 0 || options.use_login) {
Tim Rice8eff3192002-06-25 15:35:15 -0700671#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000672 /* File descriptor passing is broken or root login */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000673 use_privsep = 0;
Darren Tucker45b01422005-10-03 18:20:00 +1000674 goto skip;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000675 }
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000676
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000677 /* New socket pair */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000678 monitor_reinit(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000679
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000680 pmonitor->m_pid = fork();
681 if (pmonitor->m_pid == -1)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000682 fatal("fork of unprivileged child failed");
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000683 else if (pmonitor->m_pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000684 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000685 close(pmonitor->m_recvfd);
Darren Tuckereb578622004-08-12 23:08:14 +1000686 buffer_clear(&loginmsg);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000687 monitor_child_postauth(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000688
689 /* NEVERREACHED */
690 exit(0);
691 }
692
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000693 close(pmonitor->m_sendfd);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000694
695 /* Demote the private keys to public keys. */
696 demote_sensitive_data();
697
698 /* Drop privileges */
699 do_setusercontext(authctxt->pw);
700
Darren Tucker45b01422005-10-03 18:20:00 +1000701 skip:
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000702 /* It is safe now to apply the key state */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000703 monitor_apply_keystate(pmonitor);
Damien Miller9786e6e2005-07-26 21:54:56 +1000704
705 /*
706 * Tell the packet layer that authentication was successful, since
707 * this information is not part of the key state.
708 */
709 packet_set_authenticated();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000710}
711
Ben Lindstrombba81212001-06-25 05:01:22 +0000712static char *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100713list_hostkey_types(void)
714{
Damien Miller0e3b8722002-01-22 23:26:38 +1100715 Buffer b;
Damien Millerf58b58c2003-11-17 21:18:23 +1100716 const char *p;
717 char *ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100718 int i;
Damien Miller0e3b8722002-01-22 23:26:38 +1100719
720 buffer_init(&b);
Damien Miller9f0f5c62001-12-21 14:45:46 +1100721 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100722 Key *key = sensitive_data.host_keys[i];
723 if (key == NULL)
724 continue;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000725 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100726 case KEY_RSA:
727 case KEY_DSA:
Damien Miller0e3b8722002-01-22 23:26:38 +1100728 if (buffer_len(&b) > 0)
729 buffer_append(&b, ",", 1);
730 p = key_ssh_name(key);
731 buffer_append(&b, p, strlen(p));
Damien Miller0bc1bd82000-11-13 22:57:25 +1100732 break;
733 }
734 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100735 buffer_append(&b, "\0", 1);
Damien Millerf58b58c2003-11-17 21:18:23 +1100736 ret = xstrdup(buffer_ptr(&b));
Damien Miller0e3b8722002-01-22 23:26:38 +1100737 buffer_free(&b);
Damien Millerf58b58c2003-11-17 21:18:23 +1100738 debug("list_hostkey_types: %s", ret);
739 return ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100740}
741
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000742Key *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100743get_hostkey_by_type(int type)
744{
745 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000746
Damien Miller9f0f5c62001-12-21 14:45:46 +1100747 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100748 Key *key = sensitive_data.host_keys[i];
749 if (key != NULL && key->type == type)
750 return key;
751 }
752 return NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000753}
754
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000755Key *
756get_hostkey_by_index(int ind)
757{
758 if (ind < 0 || ind >= options.num_host_key_files)
759 return (NULL);
760 return (sensitive_data.host_keys[ind]);
761}
762
763int
764get_hostkey_index(Key *key)
765{
766 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000767
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000768 for (i = 0; i < options.num_host_key_files; i++) {
769 if (key == sensitive_data.host_keys[i])
770 return (i);
771 }
772 return (-1);
773}
774
Damien Miller942da032000-08-18 13:59:06 +1000775/*
776 * returns 1 if connection should be dropped, 0 otherwise.
777 * dropping starts at connection #max_startups_begin with a probability
778 * of (max_startups_rate/100). the probability increases linearly until
779 * all connections are dropped for startups > max_startups
780 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000781static int
Damien Miller942da032000-08-18 13:59:06 +1000782drop_connection(int startups)
783{
Darren Tucker178fa662004-11-05 20:09:09 +1100784 int p, r;
Damien Miller942da032000-08-18 13:59:06 +1000785
786 if (startups < options.max_startups_begin)
787 return 0;
788 if (startups >= options.max_startups)
789 return 1;
790 if (options.max_startups_rate == 100)
791 return 1;
792
793 p = 100 - options.max_startups_rate;
794 p *= startups - options.max_startups_begin;
Darren Tucker178fa662004-11-05 20:09:09 +1100795 p /= options.max_startups - options.max_startups_begin;
Damien Miller942da032000-08-18 13:59:06 +1000796 p += options.max_startups_rate;
Darren Tucker178fa662004-11-05 20:09:09 +1100797 r = arc4random() % 100;
Damien Miller942da032000-08-18 13:59:06 +1000798
Darren Tucker3269b132004-11-05 20:20:59 +1100799 debug("drop_connection: p %d, r %d", p, r);
Damien Miller942da032000-08-18 13:59:06 +1000800 return (r < p) ? 1 : 0;
801}
802
Ben Lindstromade03f62001-12-06 18:22:17 +0000803static void
804usage(void)
805{
Damien Miller0c889cd2004-03-22 09:36:00 +1100806 fprintf(stderr, "%s, %s\n",
Damien Miller2aa6d3c2004-09-12 16:53:04 +1000807 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
Damien Millerb4087862004-03-22 09:35:21 +1100808 fprintf(stderr,
809"usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n"
810" [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n"
811 );
Ben Lindstromade03f62001-12-06 18:22:17 +0000812 exit(1);
813}
814
Darren Tucker645ab752004-06-25 13:33:20 +1000815static void
816send_rexec_state(int fd, Buffer *conf)
817{
818 Buffer m;
819
820 debug3("%s: entering fd = %d config len %d", __func__, fd,
821 buffer_len(conf));
822
823 /*
824 * Protocol from reexec master to child:
825 * string configuration
826 * u_int ephemeral_key_follows
827 * bignum e (only if ephemeral_key_follows == 1)
828 * bignum n "
829 * bignum d "
830 * bignum iqmp "
831 * bignum p "
832 * bignum q "
Darren Tuckerc6f82192005-09-27 22:46:32 +1000833 * string rngseed (only if OpenSSL is not self-seeded)
Darren Tucker645ab752004-06-25 13:33:20 +1000834 */
835 buffer_init(&m);
836 buffer_put_cstring(&m, buffer_ptr(conf));
837
Darren Tuckerfc959702004-07-17 16:12:08 +1000838 if (sensitive_data.server_key != NULL &&
Darren Tucker645ab752004-06-25 13:33:20 +1000839 sensitive_data.server_key->type == KEY_RSA1) {
840 buffer_put_int(&m, 1);
841 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
842 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
843 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
844 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
845 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
846 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
847 } else
848 buffer_put_int(&m, 0);
849
Darren Tuckerc6f82192005-09-27 22:46:32 +1000850#ifndef OPENSSL_PRNG_ONLY
851 rexec_send_rng_seed(&m);
852#endif
853
Darren Tucker645ab752004-06-25 13:33:20 +1000854 if (ssh_msg_send(fd, 0, &m) == -1)
855 fatal("%s: ssh_msg_send failed", __func__);
856
857 buffer_free(&m);
858
859 debug3("%s: done", __func__);
860}
861
862static void
863recv_rexec_state(int fd, Buffer *conf)
864{
865 Buffer m;
866 char *cp;
867 u_int len;
868
869 debug3("%s: entering fd = %d", __func__, fd);
870
871 buffer_init(&m);
872
873 if (ssh_msg_recv(fd, &m) == -1)
874 fatal("%s: ssh_msg_recv failed", __func__);
875 if (buffer_get_char(&m) != 0)
876 fatal("%s: rexec version mismatch", __func__);
877
878 cp = buffer_get_string(&m, &len);
879 if (conf != NULL)
880 buffer_append(conf, cp, len + 1);
881 xfree(cp);
882
883 if (buffer_get_int(&m)) {
884 if (sensitive_data.server_key != NULL)
885 key_free(sensitive_data.server_key);
886 sensitive_data.server_key = key_new_private(KEY_RSA1);
887 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
888 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
889 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
890 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
891 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
892 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
893 rsa_generate_additional_parameters(
894 sensitive_data.server_key->rsa);
895 }
Darren Tuckerc6f82192005-09-27 22:46:32 +1000896
897#ifndef OPENSSL_PRNG_ONLY
898 rexec_recv_rng_seed(&m);
899#endif
900
Darren Tucker645ab752004-06-25 13:33:20 +1000901 buffer_free(&m);
902
903 debug3("%s: done", __func__);
904}
905
Damien Millera1f68402006-08-19 00:31:39 +1000906/* Accept a connection from inetd */
907static void
908server_accept_inetd(int *sock_in, int *sock_out)
909{
910 int fd;
911
912 startup_pipe = -1;
913 if (rexeced_flag) {
914 close(REEXEC_CONFIG_PASS_FD);
915 *sock_in = *sock_out = dup(STDIN_FILENO);
916 if (!debug_flag) {
917 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
918 close(REEXEC_STARTUP_PIPE_FD);
919 }
920 } else {
921 *sock_in = dup(STDIN_FILENO);
922 *sock_out = dup(STDOUT_FILENO);
923 }
924 /*
925 * We intentionally do not close the descriptors 0, 1, and 2
926 * as our code for setting the descriptors won't work if
927 * ttyfd happens to be one of those.
928 */
929 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
930 dup2(fd, STDIN_FILENO);
931 dup2(fd, STDOUT_FILENO);
932 if (fd > STDOUT_FILENO)
933 close(fd);
934 }
935 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
936}
937
938/*
939 * Listen for TCP connections
940 */
941static void
942server_listen(void)
943{
944 int ret, listen_sock, on = 1;
945 struct addrinfo *ai;
946 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
947
948 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
949 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
950 continue;
951 if (num_listen_socks >= MAX_LISTEN_SOCKS)
952 fatal("Too many listen sockets. "
953 "Enlarge MAX_LISTEN_SOCKS");
954 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
955 ntop, sizeof(ntop), strport, sizeof(strport),
956 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
957 error("getnameinfo failed: %.100s",
958 (ret != EAI_SYSTEM) ? gai_strerror(ret) :
959 strerror(errno));
960 continue;
961 }
962 /* Create socket for listening. */
963 listen_sock = socket(ai->ai_family, ai->ai_socktype,
964 ai->ai_protocol);
965 if (listen_sock < 0) {
966 /* kernel may not support ipv6 */
967 verbose("socket: %.100s", strerror(errno));
968 continue;
969 }
970 if (set_nonblock(listen_sock) == -1) {
971 close(listen_sock);
972 continue;
973 }
974 /*
975 * Set socket options.
976 * Allow local port reuse in TIME_WAIT.
977 */
978 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
979 &on, sizeof(on)) == -1)
980 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
981
982 debug("Bind to port %s on %s.", strport, ntop);
983
984 /* Bind the socket to the desired port. */
985 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
986 error("Bind to port %s on %s failed: %.200s.",
987 strport, ntop, strerror(errno));
988 close(listen_sock);
989 continue;
990 }
991 listen_socks[num_listen_socks] = listen_sock;
992 num_listen_socks++;
993
994 /* Start listening on the port. */
995 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
996 fatal("listen on [%s]:%s: %.100s",
997 ntop, strport, strerror(errno));
998 logit("Server listening on %s port %s.", ntop, strport);
999 }
1000 freeaddrinfo(options.listen_addrs);
1001
1002 if (!num_listen_socks)
1003 fatal("Cannot bind any address.");
1004}
1005
1006/*
1007 * The main TCP accept loop. Note that, for the non-debug case, returns
1008 * from this function are in a forked subprocess.
1009 */
1010static void
1011server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1012{
1013 fd_set *fdset;
1014 int i, j, ret, maxfd;
1015 int key_used = 0, startups = 0;
1016 int startup_p[2] = { -1 , -1 };
1017 struct sockaddr_storage from;
1018 socklen_t fromlen;
1019 pid_t pid;
1020
1021 /* setup fd set for accept */
1022 fdset = NULL;
1023 maxfd = 0;
1024 for (i = 0; i < num_listen_socks; i++)
1025 if (listen_socks[i] > maxfd)
1026 maxfd = listen_socks[i];
1027 /* pipes connected to unauthenticated childs */
1028 startup_pipes = xcalloc(options.max_startups, sizeof(int));
1029 for (i = 0; i < options.max_startups; i++)
1030 startup_pipes[i] = -1;
1031
1032 /*
1033 * Stay listening for connections until the system crashes or
1034 * the daemon is killed with a signal.
1035 */
1036 for (;;) {
1037 if (received_sighup)
1038 sighup_restart();
1039 if (fdset != NULL)
1040 xfree(fdset);
1041 fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS),
1042 sizeof(fd_mask));
1043
1044 for (i = 0; i < num_listen_socks; i++)
1045 FD_SET(listen_socks[i], fdset);
1046 for (i = 0; i < options.max_startups; i++)
1047 if (startup_pipes[i] != -1)
1048 FD_SET(startup_pipes[i], fdset);
1049
1050 /* Wait in select until there is a connection. */
1051 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1052 if (ret < 0 && errno != EINTR)
1053 error("select: %.100s", strerror(errno));
1054 if (received_sigterm) {
1055 logit("Received signal %d; terminating.",
1056 (int) received_sigterm);
1057 close_listen_socks();
1058 unlink(options.pid_file);
1059 exit(255);
1060 }
1061 if (key_used && key_do_regen) {
1062 generate_ephemeral_server_key();
1063 key_used = 0;
1064 key_do_regen = 0;
1065 }
1066 if (ret < 0)
1067 continue;
1068
1069 for (i = 0; i < options.max_startups; i++)
1070 if (startup_pipes[i] != -1 &&
1071 FD_ISSET(startup_pipes[i], fdset)) {
1072 /*
1073 * the read end of the pipe is ready
1074 * if the child has closed the pipe
1075 * after successful authentication
1076 * or if the child has died
1077 */
1078 close(startup_pipes[i]);
1079 startup_pipes[i] = -1;
1080 startups--;
1081 }
1082 for (i = 0; i < num_listen_socks; i++) {
1083 if (!FD_ISSET(listen_socks[i], fdset))
1084 continue;
1085 fromlen = sizeof(from);
1086 *newsock = accept(listen_socks[i],
1087 (struct sockaddr *)&from, &fromlen);
1088 if (*newsock < 0) {
1089 if (errno != EINTR && errno != EWOULDBLOCK)
1090 error("accept: %.100s", strerror(errno));
1091 continue;
1092 }
1093 if (unset_nonblock(*newsock) == -1) {
1094 close(*newsock);
1095 continue;
1096 }
1097 if (drop_connection(startups) == 1) {
1098 debug("drop connection #%d", startups);
1099 close(*newsock);
1100 continue;
1101 }
1102 if (pipe(startup_p) == -1) {
1103 close(*newsock);
1104 continue;
1105 }
1106
1107 if (rexec_flag && socketpair(AF_UNIX,
1108 SOCK_STREAM, 0, config_s) == -1) {
1109 error("reexec socketpair: %s",
1110 strerror(errno));
1111 close(*newsock);
1112 close(startup_p[0]);
1113 close(startup_p[1]);
1114 continue;
1115 }
1116
1117 for (j = 0; j < options.max_startups; j++)
1118 if (startup_pipes[j] == -1) {
1119 startup_pipes[j] = startup_p[0];
1120 if (maxfd < startup_p[0])
1121 maxfd = startup_p[0];
1122 startups++;
1123 break;
1124 }
1125
1126 /*
1127 * Got connection. Fork a child to handle it, unless
1128 * we are in debugging mode.
1129 */
1130 if (debug_flag) {
1131 /*
1132 * In debugging mode. Close the listening
1133 * socket, and start processing the
1134 * connection without forking.
1135 */
1136 debug("Server will not fork when running in debugging mode.");
1137 close_listen_socks();
1138 *sock_in = *newsock;
1139 *sock_out = *newsock;
1140 close(startup_p[0]);
1141 close(startup_p[1]);
1142 startup_pipe = -1;
1143 pid = getpid();
1144 if (rexec_flag) {
1145 send_rexec_state(config_s[0],
1146 &cfg);
1147 close(config_s[0]);
1148 }
1149 break;
1150 }
1151
1152 /*
1153 * Normal production daemon. Fork, and have
1154 * the child process the connection. The
1155 * parent continues listening.
1156 */
1157 if ((pid = fork()) == 0) {
1158 /*
1159 * Child. Close the listening and
1160 * max_startup sockets. Start using
1161 * the accepted socket. Reinitialize
1162 * logging (since our pid has changed).
1163 * We break out of the loop to handle
1164 * the connection.
1165 */
1166 startup_pipe = startup_p[1];
1167 close_startup_pipes();
1168 close_listen_socks();
1169 *sock_in = *newsock;
1170 *sock_out = *newsock;
1171 log_init(__progname,
1172 options.log_level,
1173 options.log_facility,
1174 log_stderr);
1175 if (rexec_flag)
1176 close(config_s[0]);
1177 break;
1178 }
1179
1180 /* Parent. Stay in the loop. */
1181 if (pid < 0)
1182 error("fork: %.100s", strerror(errno));
1183 else
1184 debug("Forked child %ld.", (long)pid);
1185
1186 close(startup_p[1]);
1187
1188 if (rexec_flag) {
1189 send_rexec_state(config_s[0], &cfg);
1190 close(config_s[0]);
1191 close(config_s[1]);
1192 }
1193
1194 /*
1195 * Mark that the key has been used (it
1196 * was "given" to the child).
1197 */
1198 if ((options.protocol & SSH_PROTO_1) &&
1199 key_used == 0) {
1200 /* Schedule server key regeneration alarm. */
1201 signal(SIGALRM, key_regeneration_alarm);
1202 alarm(options.key_regeneration_time);
1203 key_used = 1;
1204 }
1205
1206 close(*newsock);
1207
1208 /*
1209 * Ensure that our random state differs
1210 * from that of the child
1211 */
1212 arc4random_stir();
1213 }
1214
1215 /* child process check (or debug mode) */
1216 if (num_listen_socks < 0)
1217 break;
1218 }
1219}
1220
1221
Damien Miller95def091999-11-25 00:26:21 +11001222/*
1223 * Main program for the daemon.
1224 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001225int
1226main(int ac, char **av)
1227{
Damien Miller95def091999-11-25 00:26:21 +11001228 extern char *optarg;
1229 extern int optind;
Damien Millera1f68402006-08-19 00:31:39 +10001230 int opt, i, on = 1;
Damien Miller386c6a22004-06-30 22:40:20 +10001231 int sock_in = -1, sock_out = -1, newsock = -1;
Damien Miller95def091999-11-25 00:26:21 +11001232 const char *remote_ip;
1233 int remote_port;
Damien Millerb9997192003-12-17 16:29:22 +11001234 char *line;
Damien Millera1f68402006-08-19 00:31:39 +10001235 int config_s[2] = { -1 , -1 };
Ben Lindstromd0fca422001-03-26 13:44:06 +00001236 Key *key;
Darren Tucker3e33cec2003-10-02 16:12:36 +10001237 Authctxt *authctxt;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001238
Kevin Steves0ea1d9d2002-04-25 18:17:04 +00001239#ifdef HAVE_SECUREWARE
1240 (void)set_auth_parameters(ac, av);
1241#endif
Damien Miller59d3d5b2003-08-22 09:34:41 +10001242 __progname = ssh_get_progname(av[0]);
Damien Millerf9b625c2000-07-09 22:42:32 +10001243 init_rng();
1244
Damien Millera8ed44b2003-01-10 09:53:12 +11001245 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
Damien Millerb8c656e2000-06-28 15:22:41 +10001246 saved_argc = ac;
Darren Tucker17c5d032004-06-25 14:22:23 +10001247 rexec_argc = ac;
Darren Tuckerd8093e42006-05-04 16:24:34 +10001248 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
Damien Millera8ed44b2003-01-10 09:53:12 +11001249 for (i = 0; i < ac; i++)
1250 saved_argv[i] = xstrdup(av[i]);
Damien Miller04cb5362003-05-15 21:29:10 +10001251 saved_argv[i] = NULL;
Damien Millera8ed44b2003-01-10 09:53:12 +11001252
1253#ifndef HAVE_SETPROCTITLE
1254 /* Prepare for later setproctitle emulation */
1255 compat_init_setproctitle(ac, av);
Damien Millerf2e3e9d2003-06-02 12:15:54 +10001256 av = saved_argv;
Damien Millera8ed44b2003-01-10 09:53:12 +11001257#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001258
Damien Millerbfba3542004-03-22 09:29:57 +11001259 if (geteuid() == 0 && setgroups(0, NULL) == -1)
1260 debug("setgroups(): %.200s", strerror(errno));
1261
Darren Tuckerce321d82005-10-03 18:11:24 +10001262 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1263 sanitise_stdfd();
1264
Damien Miller95def091999-11-25 00:26:21 +11001265 /* Initialize configuration options to their default values. */
1266 initialize_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001267
Damien Miller95def091999-11-25 00:26:21 +11001268 /* Parse command-line arguments. */
Darren Tucker645ab752004-06-25 13:33:20 +10001269 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) {
Damien Miller95def091999-11-25 00:26:21 +11001270 switch (opt) {
Damien Miller34132e52000-01-14 15:45:46 +11001271 case '4':
Darren Tucker0f383232005-01-20 10:57:56 +11001272 options.address_family = AF_INET;
Damien Miller34132e52000-01-14 15:45:46 +11001273 break;
1274 case '6':
Darren Tucker0f383232005-01-20 10:57:56 +11001275 options.address_family = AF_INET6;
Damien Miller34132e52000-01-14 15:45:46 +11001276 break;
Damien Miller95def091999-11-25 00:26:21 +11001277 case 'f':
1278 config_file_name = optarg;
1279 break;
1280 case 'd':
Darren Tuckere98dfa32003-07-19 19:54:31 +10001281 if (debug_flag == 0) {
Damien Millere4340be2000-09-16 13:29:08 +11001282 debug_flag = 1;
1283 options.log_level = SYSLOG_LEVEL_DEBUG1;
Darren Tuckere98dfa32003-07-19 19:54:31 +10001284 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
Damien Millere4340be2000-09-16 13:29:08 +11001285 options.log_level++;
Damien Miller95def091999-11-25 00:26:21 +11001286 break;
Ben Lindstromc72745a2000-12-02 19:03:54 +00001287 case 'D':
1288 no_daemon_flag = 1;
1289 break;
Ben Lindstrom9fce9f02001-04-11 23:10:09 +00001290 case 'e':
1291 log_stderr = 1;
1292 break;
Damien Miller95def091999-11-25 00:26:21 +11001293 case 'i':
1294 inetd_flag = 1;
1295 break;
Darren Tucker645ab752004-06-25 13:33:20 +10001296 case 'r':
1297 rexec_flag = 0;
1298 break;
1299 case 'R':
1300 rexeced_flag = 1;
1301 inetd_flag = 1;
1302 break;
Damien Miller95def091999-11-25 00:26:21 +11001303 case 'Q':
Ben Lindstromd5390202001-01-29 08:07:43 +00001304 /* ignored */
Damien Miller95def091999-11-25 00:26:21 +11001305 break;
1306 case 'q':
1307 options.log_level = SYSLOG_LEVEL_QUIET;
1308 break;
1309 case 'b':
Damien Millerf0b15df2006-03-26 13:59:20 +11001310 options.server_key_bits = (int)strtonum(optarg, 256,
1311 32768, NULL);
Damien Miller95def091999-11-25 00:26:21 +11001312 break;
1313 case 'p':
Damien Miller34132e52000-01-14 15:45:46 +11001314 options.ports_from_cmdline = 1;
Damien Millere4340be2000-09-16 13:29:08 +11001315 if (options.num_ports >= MAX_PORTS) {
1316 fprintf(stderr, "too many ports.\n");
1317 exit(1);
1318 }
Ben Lindstrom19066a12001-04-12 23:39:26 +00001319 options.ports[options.num_ports++] = a2port(optarg);
1320 if (options.ports[options.num_ports-1] == 0) {
1321 fprintf(stderr, "Bad port number.\n");
1322 exit(1);
1323 }
Damien Miller95def091999-11-25 00:26:21 +11001324 break;
1325 case 'g':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +00001326 if ((options.login_grace_time = convtime(optarg)) == -1) {
1327 fprintf(stderr, "Invalid login grace time.\n");
1328 exit(1);
1329 }
Damien Miller95def091999-11-25 00:26:21 +11001330 break;
1331 case 'k':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +00001332 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
1333 fprintf(stderr, "Invalid key regeneration interval.\n");
1334 exit(1);
1335 }
Damien Miller95def091999-11-25 00:26:21 +11001336 break;
1337 case 'h':
Damien Miller0bc1bd82000-11-13 22:57:25 +11001338 if (options.num_host_key_files >= MAX_HOSTKEYS) {
1339 fprintf(stderr, "too many host keys.\n");
1340 exit(1);
1341 }
1342 options.host_key_files[options.num_host_key_files++] = optarg;
Damien Miller95def091999-11-25 00:26:21 +11001343 break;
Ben Lindstrom794325a2001-08-06 21:09:07 +00001344 case 't':
1345 test_flag = 1;
1346 break;
Damien Miller942da032000-08-18 13:59:06 +10001347 case 'u':
Damien Millerf0b15df2006-03-26 13:59:20 +11001348 utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL);
Ben Lindstrom41daec72002-07-23 21:15:13 +00001349 if (utmp_len > MAXHOSTNAMELEN) {
1350 fprintf(stderr, "Invalid utmp length.\n");
1351 exit(1);
1352 }
Damien Miller942da032000-08-18 13:59:06 +10001353 break;
Ben Lindstromade03f62001-12-06 18:22:17 +00001354 case 'o':
Damien Millerb9997192003-12-17 16:29:22 +11001355 line = xstrdup(optarg);
1356 if (process_server_config_line(&options, line,
Darren Tucker45150472006-07-12 22:34:17 +10001357 "command-line", 0, NULL, NULL, NULL, NULL) != 0)
Damien Miller9f0f5c62001-12-21 14:45:46 +11001358 exit(1);
Damien Millerb9997192003-12-17 16:29:22 +11001359 xfree(line);
Ben Lindstromade03f62001-12-06 18:22:17 +00001360 break;
Damien Miller95def091999-11-25 00:26:21 +11001361 case '?':
1362 default:
Ben Lindstromade03f62001-12-06 18:22:17 +00001363 usage();
1364 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001365 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001366 }
Darren Tucker645ab752004-06-25 13:33:20 +10001367 if (rexeced_flag || inetd_flag)
1368 rexec_flag = 0;
1369 if (rexec_flag && (av[0] == NULL || *av[0] != '/'))
1370 fatal("sshd re-exec requires execution with an absolute path");
1371 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001372 closefrom(REEXEC_MIN_FREE_FD);
1373 else
1374 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001375
Ben Lindstrom425fb022001-03-29 00:31:20 +00001376 SSLeay_add_all_algorithms();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001377
Damien Miller34132e52000-01-14 15:45:46 +11001378 /*
1379 * Force logging to stderr until we have loaded the private host
1380 * key (unless started from inetd)
1381 */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001382 log_init(__progname,
Damien Miller5aa5d782002-02-08 22:01:54 +11001383 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1384 SYSLOG_LEVEL_INFO : options.log_level,
1385 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1386 SYSLOG_FACILITY_AUTH : options.log_facility,
Ben Lindstromc2faa4a2002-11-09 15:50:03 +00001387 log_stderr || !inetd_flag);
Damien Miller34132e52000-01-14 15:45:46 +11001388
Darren Tucker86c093d2004-03-08 22:59:03 +11001389 /*
1390 * Unset KRB5CCNAME, otherwise the user's session may inherit it from
1391 * root's environment
Damien Miller94cf4c82005-07-17 17:04:47 +10001392 */
Darren Tucker9dc6c7d2005-02-02 18:30:33 +11001393 if (getenv("KRB5CCNAME") != NULL)
1394 unsetenv("KRB5CCNAME");
1395
Tim Rice81ed5182002-09-25 17:38:46 -07001396#ifdef _UNICOS
Darren Tucker12984962004-05-24 13:37:13 +10001397 /* Cray can define user privs drop all privs now!
Ben Lindstrom6db66ff2001-08-06 23:29:16 +00001398 * Not needed on PRIV_SU systems!
1399 */
1400 drop_cray_privs();
1401#endif
1402
Darren Tucker645ab752004-06-25 13:33:20 +10001403 sensitive_data.server_key = NULL;
1404 sensitive_data.ssh1_host_key = NULL;
1405 sensitive_data.have_ssh1_key = 0;
1406 sensitive_data.have_ssh2_key = 0;
1407
1408 /* Fetch our configuration */
1409 buffer_init(&cfg);
1410 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001411 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
Darren Tucker645ab752004-06-25 13:33:20 +10001412 else
1413 load_server_config(config_file_name, &cfg);
1414
Darren Tucker45150472006-07-12 22:34:17 +10001415 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1416 &cfg, NULL, NULL, NULL);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001417
Darren Tuckerc6f82192005-09-27 22:46:32 +10001418 seed_rng();
1419
Damien Miller95def091999-11-25 00:26:21 +11001420 /* Fill in default values for those options not explicitly set. */
1421 fill_default_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001422
Darren Tucker0f383232005-01-20 10:57:56 +11001423 /* set default channel AF */
1424 channel_set_af(options.address_family);
1425
Damien Miller95def091999-11-25 00:26:21 +11001426 /* Check that there are no remaining arguments. */
1427 if (optind < ac) {
1428 fprintf(stderr, "Extra argument %s.\n", av[optind]);
1429 exit(1);
1430 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001431
Damien Miller2aa6d3c2004-09-12 16:53:04 +10001432 debug("sshd version %.100s", SSH_RELEASE);
Damien Miller2ccf6611999-11-15 15:25:10 +11001433
Damien Miller0bc1bd82000-11-13 22:57:25 +11001434 /* load private host keys */
Damien Miller07d86be2006-03-26 14:19:21 +11001435 sensitive_data.host_keys = xcalloc(options.num_host_key_files,
Ben Lindstroma962c2f2002-07-04 00:14:17 +00001436 sizeof(Key *));
Damien Miller9f0f5c62001-12-21 14:45:46 +11001437 for (i = 0; i < options.num_host_key_files; i++)
Ben Lindstrom46c16222000-12-22 01:43:59 +00001438 sensitive_data.host_keys[i] = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +10001439
Damien Miller9f0f5c62001-12-21 14:45:46 +11001440 for (i = 0; i < options.num_host_key_files; i++) {
Ben Lindstromd0fca422001-03-26 13:44:06 +00001441 key = key_load_private(options.host_key_files[i], "", NULL);
1442 sensitive_data.host_keys[i] = key;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001443 if (key == NULL) {
Ben Lindstrom15f33862001-04-16 02:00:02 +00001444 error("Could not load host key: %s",
1445 options.host_key_files[i]);
Ben Lindstromd0fca422001-03-26 13:44:06 +00001446 sensitive_data.host_keys[i] = NULL;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001447 continue;
1448 }
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +00001449 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +11001450 case KEY_RSA1:
1451 sensitive_data.ssh1_host_key = key;
1452 sensitive_data.have_ssh1_key = 1;
1453 break;
1454 case KEY_RSA:
1455 case KEY_DSA:
1456 sensitive_data.have_ssh2_key = 1;
1457 break;
1458 }
Ben Lindstromd0fca422001-03-26 13:44:06 +00001459 debug("private host key: #%d type %d %s", i, key->type,
1460 key_type(key));
Damien Miller0bc1bd82000-11-13 22:57:25 +11001461 }
1462 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001463 logit("Disabling protocol version 1. Could not load host key");
Damien Millereba71ba2000-04-29 23:57:08 +10001464 options.protocol &= ~SSH_PROTO_1;
1465 }
Damien Miller0bc1bd82000-11-13 22:57:25 +11001466 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001467 logit("Disabling protocol version 2. Could not load host key");
Damien Miller0bc1bd82000-11-13 22:57:25 +11001468 options.protocol &= ~SSH_PROTO_2;
Damien Millereba71ba2000-04-29 23:57:08 +10001469 }
Kevin Stevesadf74cd2001-02-05 14:22:50 +00001470 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
Damien Miller996acd22003-04-09 20:59:48 +10001471 logit("sshd: no hostkeys available -- exiting.");
Damien Miller95def091999-11-25 00:26:21 +11001472 exit(1);
1473 }
Damien Miller95def091999-11-25 00:26:21 +11001474
Damien Millereba71ba2000-04-29 23:57:08 +10001475 /* Check certain values for sanity. */
1476 if (options.protocol & SSH_PROTO_1) {
1477 if (options.server_key_bits < 512 ||
1478 options.server_key_bits > 32768) {
1479 fprintf(stderr, "Bad server key size.\n");
1480 exit(1);
1481 }
1482 /*
1483 * Check that server and host key lengths differ sufficiently. This
1484 * is necessary to make double encryption work with rsaref. Oh, I
1485 * hate software patents. I dont know if this can go? Niels
1486 */
1487 if (options.server_key_bits >
Ben Lindstrom822b6342002-06-23 21:38:49 +00001488 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1489 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1490 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1491 SSH_KEY_BITS_RESERVED) {
Damien Millereba71ba2000-04-29 23:57:08 +10001492 options.server_key_bits =
Ben Lindstrom822b6342002-06-23 21:38:49 +00001493 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1494 SSH_KEY_BITS_RESERVED;
Damien Millereba71ba2000-04-29 23:57:08 +10001495 debug("Forcing server key to %d bits to make it differ from host key.",
1496 options.server_key_bits);
1497 }
1498 }
1499
Ben Lindstroma26ea632002-06-06 20:46:25 +00001500 if (use_privsep) {
Ben Lindstroma26ea632002-06-06 20:46:25 +00001501 struct stat st;
1502
Damien Millerf0b15df2006-03-26 13:59:20 +11001503 if (getpwnam(SSH_PRIVSEP_USER) == NULL)
Ben Lindstroma26ea632002-06-06 20:46:25 +00001504 fatal("Privilege separation user %s does not exist",
1505 SSH_PRIVSEP_USER);
1506 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1507 (S_ISDIR(st.st_mode) == 0))
1508 fatal("Missing privilege separation directory: %s",
1509 _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstrom59627352002-06-27 18:02:21 +00001510
1511#ifdef HAVE_CYGWIN
1512 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1513 (st.st_uid != getuid () ||
1514 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1515#else
Ben Lindstrom2dfacb32002-06-23 00:33:47 +00001516 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
Ben Lindstrom59627352002-06-27 18:02:21 +00001517#endif
Damien Miller180fc5b2003-02-24 11:50:18 +11001518 fatal("%s must be owned by root and not group or "
1519 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstroma26ea632002-06-06 20:46:25 +00001520 }
1521
Ben Lindstrom794325a2001-08-06 21:09:07 +00001522 /* Configuration looks good, so exit if in test mode. */
1523 if (test_flag)
1524 exit(0);
1525
Damien Miller87aea252002-05-10 12:20:24 +10001526 /*
1527 * Clear out any supplemental groups we may have inherited. This
1528 * prevents inadvertent creation of files with bad modes (in the
Damien Millera8e06ce2003-11-21 23:48:55 +11001529 * portable version at least, it's certainly possible for PAM
1530 * to create a file, and we can't control the code in every
Damien Miller87aea252002-05-10 12:20:24 +10001531 * module which might be used).
1532 */
1533 if (setgroups(0, NULL) < 0)
1534 debug("setgroups() failed: %.200s", strerror(errno));
1535
Darren Tucker645ab752004-06-25 13:33:20 +10001536 if (rexec_flag) {
Damien Miller07d86be2006-03-26 14:19:21 +11001537 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
Darren Tucker645ab752004-06-25 13:33:20 +10001538 for (i = 0; i < rexec_argc; i++) {
1539 debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1540 rexec_argv[i] = saved_argv[i];
1541 }
1542 rexec_argv[rexec_argc] = "-R";
1543 rexec_argv[rexec_argc + 1] = NULL;
1544 }
1545
Damien Millereba71ba2000-04-29 23:57:08 +10001546 /* Initialize the log (it is reinitialized below in case we forked). */
Darren Tuckerea7c8122005-01-20 11:03:08 +11001547 if (debug_flag && (!inetd_flag || rexeced_flag))
Damien Miller95def091999-11-25 00:26:21 +11001548 log_stderr = 1;
Kevin Stevesec84dc12000-12-13 17:45:15 +00001549 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001550
Damien Millereba71ba2000-04-29 23:57:08 +10001551 /*
1552 * If not in debugging mode, and not started from inetd, disconnect
1553 * from the controlling terminal, and fork. The original process
1554 * exits.
1555 */
Ben Lindstromc72745a2000-12-02 19:03:54 +00001556 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
Damien Miller95def091999-11-25 00:26:21 +11001557#ifdef TIOCNOTTY
1558 int fd;
1559#endif /* TIOCNOTTY */
1560 if (daemon(0, 0) < 0)
1561 fatal("daemon() failed: %.200s", strerror(errno));
1562
1563 /* Disconnect from the controlling tty. */
1564#ifdef TIOCNOTTY
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001565 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +11001566 if (fd >= 0) {
1567 (void) ioctl(fd, TIOCNOTTY, NULL);
1568 close(fd);
1569 }
1570#endif /* TIOCNOTTY */
1571 }
1572 /* Reinitialize the log (because of the fork above). */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001573 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001574
Damien Miller95def091999-11-25 00:26:21 +11001575 /* Initialize the random number generator. */
1576 arc4random_stir();
1577
1578 /* Chdir to the root directory so that the current disk can be
1579 unmounted if desired. */
1580 chdir("/");
Damien Miller9f0f5c62001-12-21 14:45:46 +11001581
Ben Lindstromde71cda2001-03-24 00:43:26 +00001582 /* ignore SIGPIPE */
1583 signal(SIGPIPE, SIG_IGN);
Damien Miller95def091999-11-25 00:26:21 +11001584
Damien Millera1f68402006-08-19 00:31:39 +10001585 /* Get a connection, either from inetd or a listening TCP socket */
Damien Miller95def091999-11-25 00:26:21 +11001586 if (inetd_flag) {
Damien Millera1f68402006-08-19 00:31:39 +10001587 server_accept_inetd(&sock_in, &sock_out);
Darren Tucker645ab752004-06-25 13:33:20 +10001588
Darren Tucker645ab752004-06-25 13:33:20 +10001589 if ((options.protocol & SSH_PROTO_1) &&
1590 sensitive_data.server_key == NULL)
Ben Lindstromca42d5f2001-03-09 18:25:32 +00001591 generate_ephemeral_server_key();
Damien Miller95def091999-11-25 00:26:21 +11001592 } else {
Damien Millera1f68402006-08-19 00:31:39 +10001593 server_listen();
Damien Miller34132e52000-01-14 15:45:46 +11001594
Ben Lindstrom98097862001-06-25 05:10:20 +00001595 if (options.protocol & SSH_PROTO_1)
1596 generate_ephemeral_server_key();
1597
Ben Lindstrom98097862001-06-25 05:10:20 +00001598 signal(SIGHUP, sighup_handler);
Damien Millera1f68402006-08-19 00:31:39 +10001599 signal(SIGCHLD, main_sigchld_handler);
Ben Lindstrom98097862001-06-25 05:10:20 +00001600 signal(SIGTERM, sigterm_handler);
1601 signal(SIGQUIT, sigterm_handler);
1602
Damien Millera1f68402006-08-19 00:31:39 +10001603 /*
1604 * Write out the pid file after the sigterm handler
1605 * is setup and the listen sockets are bound
1606 */
Damien Miller95def091999-11-25 00:26:21 +11001607 if (!debug_flag) {
Damien Millera1f68402006-08-19 00:31:39 +10001608 FILE *f = fopen(options.pid_file, "w");
1609
Darren Tuckere5327042003-07-03 13:40:44 +10001610 if (f == NULL) {
1611 error("Couldn't create pid file \"%s\": %s",
1612 options.pid_file, strerror(errno));
1613 } else {
Ben Lindstromce0f6342002-06-11 16:42:49 +00001614 fprintf(f, "%ld\n", (long) getpid());
Damien Miller95def091999-11-25 00:26:21 +11001615 fclose(f);
1616 }
1617 }
Damien Miller95def091999-11-25 00:26:21 +11001618
Damien Millera1f68402006-08-19 00:31:39 +10001619 /* Accept a connection and return in a forked child */
1620 server_accept_loop(&sock_in, &sock_out,
1621 &newsock, config_s);
Damien Miller95def091999-11-25 00:26:21 +11001622 }
1623
1624 /* This is the child processing a new connection. */
Damien Miller57aae982004-03-08 23:11:25 +11001625 setproctitle("%s", "[accepted]");
Damien Miller95def091999-11-25 00:26:21 +11001626
Darren Tucker6832b832004-08-12 22:36:51 +10001627 /*
1628 * Create a new session and process group since the 4.4BSD
1629 * setlogin() affects the entire process group. We don't
1630 * want the child to be able to affect the parent.
1631 */
1632#if !defined(SSHD_ACQUIRES_CTTY)
1633 /*
1634 * If setsid is called, on some platforms sshd will later acquire a
1635 * controlling terminal which will result in "could not set
1636 * controlling tty" errors.
1637 */
1638 if (!debug_flag && !inetd_flag && setsid() < 0)
1639 error("setsid: %.100s", strerror(errno));
1640#endif
1641
Darren Tucker645ab752004-06-25 13:33:20 +10001642 if (rexec_flag) {
1643 int fd;
1644
Damien Miller035a5b42004-06-26 08:16:31 +10001645 debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1646 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001647 dup2(newsock, STDIN_FILENO);
1648 dup2(STDIN_FILENO, STDOUT_FILENO);
1649 if (startup_pipe == -1)
Damien Miller035a5b42004-06-26 08:16:31 +10001650 close(REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001651 else
Damien Miller035a5b42004-06-26 08:16:31 +10001652 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001653
Damien Miller035a5b42004-06-26 08:16:31 +10001654 dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001655 close(config_s[1]);
Darren Tuckerd8835932004-08-12 22:42:29 +10001656 if (startup_pipe != -1)
1657 close(startup_pipe);
Damien Miller035a5b42004-06-26 08:16:31 +10001658
Darren Tucker645ab752004-06-25 13:33:20 +10001659 execv(rexec_argv[0], rexec_argv);
1660
1661 /* Reexec has failed, fall back and continue */
1662 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
Damien Miller035a5b42004-06-26 08:16:31 +10001663 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
Darren Tucker645ab752004-06-25 13:33:20 +10001664 log_init(__progname, options.log_level,
1665 options.log_facility, log_stderr);
1666
1667 /* Clean up fds */
Damien Miller035a5b42004-06-26 08:16:31 +10001668 startup_pipe = REEXEC_STARTUP_PIPE_FD;
Darren Tucker645ab752004-06-25 13:33:20 +10001669 close(config_s[1]);
Damien Miller035a5b42004-06-26 08:16:31 +10001670 close(REEXEC_CONFIG_PASS_FD);
1671 newsock = sock_out = sock_in = dup(STDIN_FILENO);
Darren Tucker645ab752004-06-25 13:33:20 +10001672 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1673 dup2(fd, STDIN_FILENO);
1674 dup2(fd, STDOUT_FILENO);
1675 if (fd > STDERR_FILENO)
1676 close(fd);
1677 }
Damien Miller035a5b42004-06-26 08:16:31 +10001678 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1679 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001680 }
1681
Damien Miller5428f641999-11-25 11:54:57 +11001682 /*
1683 * Disable the key regeneration alarm. We will not regenerate the
1684 * key since we are no longer in a position to give it to anyone. We
1685 * will not restart on SIGHUP since it no longer makes sense.
1686 */
Damien Miller95def091999-11-25 00:26:21 +11001687 alarm(0);
1688 signal(SIGALRM, SIG_DFL);
1689 signal(SIGHUP, SIG_DFL);
1690 signal(SIGTERM, SIG_DFL);
1691 signal(SIGQUIT, SIG_DFL);
1692 signal(SIGCHLD, SIG_DFL);
Damien Miller4e0f5e12000-08-29 11:05:50 +11001693 signal(SIGINT, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +11001694
Damien Miller5428f641999-11-25 11:54:57 +11001695 /*
1696 * Register our connection. This turns encryption off because we do
1697 * not have a key.
1698 */
Damien Miller95def091999-11-25 00:26:21 +11001699 packet_set_connection(sock_in, sock_out);
Damien Miller9786e6e2005-07-26 21:54:56 +10001700 packet_set_server();
Damien Miller95def091999-11-25 00:26:21 +11001701
Damien Miller4f1d6b22005-05-26 11:59:32 +10001702 /* Set SO_KEEPALIVE if requested. */
1703 if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1704 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1705 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1706
Damien Miller677257f2005-06-17 12:55:03 +10001707 if ((remote_port = get_remote_port()) < 0) {
1708 debug("get_remote_port failed");
1709 cleanup_exit(255);
1710 }
Damien Miller4d3fd542005-11-05 15:13:24 +11001711
1712 /*
1713 * We use get_canonical_hostname with usedns = 0 instead of
1714 * get_remote_ipaddr here so IP options will be checked.
1715 */
Damien Millereb13e552006-06-13 13:03:53 +10001716 (void) get_canonical_hostname(0);
1717 /*
1718 * The rest of the code depends on the fact that
1719 * get_remote_ipaddr() caches the remote ip, even if
1720 * the socket goes away.
1721 */
1722 remote_ip = get_remote_ipaddr();
Damien Miller95def091999-11-25 00:26:21 +11001723
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001724#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11001725 audit_connection_from(remote_ip, remote_port);
1726#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001727#ifdef LIBWRAP
Damien Miller6a4a4b92001-11-12 11:07:11 +11001728 /* Check whether logins are denied from this host. */
Darren Tucker586b0b92004-06-25 13:34:31 +10001729 if (packet_connection_is_on_socket()) {
Damien Miller95def091999-11-25 00:26:21 +11001730 struct request_info req;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001731
Ben Lindstromce89dac2001-09-12 16:58:04 +00001732 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
Damien Miller95def091999-11-25 00:26:21 +11001733 fromhost(&req);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001734
Damien Miller95def091999-11-25 00:26:21 +11001735 if (!hosts_access(&req)) {
Damien Miller6a4a4b92001-11-12 11:07:11 +11001736 debug("Connection refused by tcp wrapper");
Ben Lindstrom7de696e2001-03-29 00:45:12 +00001737 refuse(&req);
Damien Miller6a4a4b92001-11-12 11:07:11 +11001738 /* NOTREACHED */
1739 fatal("libwrap refuse returns");
Damien Miller95def091999-11-25 00:26:21 +11001740 }
Damien Miller95def091999-11-25 00:26:21 +11001741 }
Damien Miller34132e52000-01-14 15:45:46 +11001742#endif /* LIBWRAP */
Damien Miller6a4a4b92001-11-12 11:07:11 +11001743
Damien Miller95def091999-11-25 00:26:21 +11001744 /* Log the connection. */
1745 verbose("Connection from %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001746
Damien Miller5428f641999-11-25 11:54:57 +11001747 /*
Damien Miller788f2122005-11-05 15:14:59 +11001748 * We don't want to listen forever unless the other side
Damien Miller5428f641999-11-25 11:54:57 +11001749 * successfully authenticates itself. So we set up an alarm which is
1750 * cleared after successful authentication. A limit of zero
Damien Miller788f2122005-11-05 15:14:59 +11001751 * indicates no limit. Note that we don't set the alarm in debugging
Damien Miller5428f641999-11-25 11:54:57 +11001752 * mode; it is just annoying to have the server exit just when you
1753 * are about to discover the bug.
1754 */
Ben Lindstrom5ade9ab2003-08-25 01:16:21 +00001755 signal(SIGALRM, grace_alarm_handler);
Damien Miller95def091999-11-25 00:26:21 +11001756 if (!debug_flag)
1757 alarm(options.login_grace_time);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001758
Damien Millerb38eff82000-04-01 11:09:21 +10001759 sshd_exchange_identification(sock_in, sock_out);
Darren Tuckerec960f22003-08-13 20:37:05 +10001760
Damien Miller95def091999-11-25 00:26:21 +11001761 packet_set_nonblocking();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001762
Darren Tucker3e33cec2003-10-02 16:12:36 +10001763 /* allocate authentication context */
Damien Miller07d86be2006-03-26 14:19:21 +11001764 authctxt = xcalloc(1, sizeof(*authctxt));
Darren Tucker3e33cec2003-10-02 16:12:36 +10001765
Darren Tuckerf3bb4342005-03-31 21:39:25 +10001766 authctxt->loginmsg = &loginmsg;
1767
Darren Tucker3e33cec2003-10-02 16:12:36 +10001768 /* XXX global for cleanup, access from other modules */
1769 the_authctxt = authctxt;
1770
Darren Tucker5c14c732005-01-24 21:55:49 +11001771 /* prepare buffer to collect messages to display to user after login */
1772 buffer_init(&loginmsg);
1773
Ben Lindstrom943481c2002-03-22 03:43:46 +00001774 if (use_privsep)
Darren Tucker3e33cec2003-10-02 16:12:36 +10001775 if (privsep_preauth(authctxt) == 1)
Ben Lindstrom943481c2002-03-22 03:43:46 +00001776 goto authenticated;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001777
Damien Miller396691a2000-01-20 22:44:08 +11001778 /* perform the key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001779 /* authenticate user and start session */
Damien Millerefb4afe2000-04-12 18:45:05 +10001780 if (compat20) {
1781 do_ssh2_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001782 do_authentication2(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001783 } else {
1784 do_ssh1_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001785 do_authentication(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001786 }
Ben Lindstrom943481c2002-03-22 03:43:46 +00001787 /*
1788 * If we use privilege separation, the unprivileged child transfers
1789 * the current keystate and exits
1790 */
1791 if (use_privsep) {
Ben Lindstrom7339b2a2002-05-15 16:25:01 +00001792 mm_send_keystate(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001793 exit(0);
Ben Lindstrom943481c2002-03-22 03:43:46 +00001794 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001795
1796 authenticated:
Damien Miller7bff1a92005-12-24 14:59:12 +11001797 /*
1798 * Cancel the alarm we set to limit the time taken for
1799 * authentication.
1800 */
1801 alarm(0);
1802 signal(SIGALRM, SIG_DFL);
Damien Miller3f8123c2006-08-19 00:32:46 +10001803 authctxt->authenticated = 1;
Damien Miller7bff1a92005-12-24 14:59:12 +11001804 if (startup_pipe != -1) {
1805 close(startup_pipe);
1806 startup_pipe = -1;
1807 }
1808
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001809#ifdef SSH_AUDIT_EVENTS
1810 audit_event(SSH_AUTH_SUCCESS);
Darren Tucker269a1ea2005-02-03 00:20:53 +11001811#endif
1812
Ben Lindstrom6328ab32002-03-22 02:54:23 +00001813 /*
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001814 * In privilege separation, we fork another child and prepare
1815 * file descriptor passing.
1816 */
1817 if (use_privsep) {
Ben Lindstrom943481c2002-03-22 03:43:46 +00001818 privsep_postauth(authctxt);
1819 /* the monitor process [priv] will not return */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001820 if (!compat20)
1821 destroy_sensitive_data();
1822 }
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001823
Darren Tucker3e33cec2003-10-02 16:12:36 +10001824 /* Start session. */
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001825 do_authenticated(authctxt);
1826
Damien Miller3a5b0232002-03-13 13:19:42 +11001827 /* The connection has been terminated. */
1828 verbose("Closing connection to %.100s", remote_ip);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001829
Damien Millerbeb4ba51999-12-28 15:09:35 +11001830#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +10001831 if (options.use_pam)
1832 finish_pam();
Damien Millerbeb4ba51999-12-28 15:09:35 +11001833#endif /* USE_PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001834
Darren Tucker2b59a6d2005-03-06 22:38:51 +11001835#ifdef SSH_AUDIT_EVENTS
1836 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE));
1837#endif
1838
Damien Miller95def091999-11-25 00:26:21 +11001839 packet_close();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001840
1841 if (use_privsep)
1842 mm_terminate();
1843
Damien Miller95def091999-11-25 00:26:21 +11001844 exit(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001845}
1846
Damien Miller95def091999-11-25 00:26:21 +11001847/*
Ben Lindstromabcb1452002-03-22 01:10:21 +00001848 * Decrypt session_key_int using our private server key and private host key
1849 * (key with larger modulus first).
1850 */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001851int
Ben Lindstromabcb1452002-03-22 01:10:21 +00001852ssh1_session_key(BIGNUM *session_key_int)
1853{
1854 int rsafail = 0;
1855
Damien Millerf0b15df2006-03-26 13:59:20 +11001856 if (BN_cmp(sensitive_data.server_key->rsa->n,
1857 sensitive_data.ssh1_host_key->rsa->n) > 0) {
Ben Lindstromabcb1452002-03-22 01:10:21 +00001858 /* Server key has bigger modulus. */
1859 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
Damien Millerf0b15df2006-03-26 13:59:20 +11001860 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1861 SSH_KEY_BITS_RESERVED) {
1862 fatal("do_connection: %s: "
1863 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
Ben Lindstromabcb1452002-03-22 01:10:21 +00001864 get_remote_ipaddr(),
1865 BN_num_bits(sensitive_data.server_key->rsa->n),
1866 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1867 SSH_KEY_BITS_RESERVED);
1868 }
1869 if (rsa_private_decrypt(session_key_int, session_key_int,
1870 sensitive_data.server_key->rsa) <= 0)
1871 rsafail++;
1872 if (rsa_private_decrypt(session_key_int, session_key_int,
1873 sensitive_data.ssh1_host_key->rsa) <= 0)
1874 rsafail++;
1875 } else {
1876 /* Host key has bigger modulus (or they are equal). */
1877 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
Damien Millerf0b15df2006-03-26 13:59:20 +11001878 BN_num_bits(sensitive_data.server_key->rsa->n) +
1879 SSH_KEY_BITS_RESERVED) {
1880 fatal("do_connection: %s: "
1881 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
Ben Lindstromabcb1452002-03-22 01:10:21 +00001882 get_remote_ipaddr(),
1883 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1884 BN_num_bits(sensitive_data.server_key->rsa->n),
1885 SSH_KEY_BITS_RESERVED);
1886 }
1887 if (rsa_private_decrypt(session_key_int, session_key_int,
1888 sensitive_data.ssh1_host_key->rsa) < 0)
1889 rsafail++;
1890 if (rsa_private_decrypt(session_key_int, session_key_int,
1891 sensitive_data.server_key->rsa) < 0)
1892 rsafail++;
1893 }
1894 return (rsafail);
1895}
1896/*
Damien Miller396691a2000-01-20 22:44:08 +11001897 * SSH1 key exchange
Damien Miller95def091999-11-25 00:26:21 +11001898 */
Ben Lindstrombba81212001-06-25 05:01:22 +00001899static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001900do_ssh1_kex(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001901{
Damien Miller95def091999-11-25 00:26:21 +11001902 int i, len;
Damien Miller7650bc62001-01-30 09:27:26 +11001903 int rsafail = 0;
Damien Miller95def091999-11-25 00:26:21 +11001904 BIGNUM *session_key_int;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001905 u_char session_key[SSH_SESSION_KEY_LENGTH];
1906 u_char cookie[8];
1907 u_int cipher_type, auth_mask, protocol_flags;
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001908 u_int32_t rnd = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001909
Damien Miller5428f641999-11-25 11:54:57 +11001910 /*
1911 * Generate check bytes that the client must send back in the user
1912 * packet in order for it to be accepted; this is used to defy ip
1913 * spoofing attacks. Note that this only works against somebody
1914 * doing IP spoofing from a remote machine; any machine on the local
1915 * network can still see outgoing packets and catch the random
1916 * cookie. This only affects rhosts authentication, and this is one
1917 * of the reasons why it is inherently insecure.
1918 */
Damien Miller95def091999-11-25 00:26:21 +11001919 for (i = 0; i < 8; i++) {
1920 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001921 rnd = arc4random();
1922 cookie[i] = rnd & 0xff;
1923 rnd >>= 8;
Damien Miller95def091999-11-25 00:26:21 +11001924 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001925
Damien Miller5428f641999-11-25 11:54:57 +11001926 /*
1927 * Send our public key. We include in the packet 64 bits of random
1928 * data that must be matched in the reply in order to prevent IP
1929 * spoofing.
1930 */
Damien Miller95def091999-11-25 00:26:21 +11001931 packet_start(SSH_SMSG_PUBLIC_KEY);
1932 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001933 packet_put_char(cookie[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001934
Damien Miller95def091999-11-25 00:26:21 +11001935 /* Store our public server RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001936 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1937 packet_put_bignum(sensitive_data.server_key->rsa->e);
1938 packet_put_bignum(sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001939
Damien Miller95def091999-11-25 00:26:21 +11001940 /* Store our public host RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001941 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1942 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1943 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001944
Damien Miller95def091999-11-25 00:26:21 +11001945 /* Put protocol flags. */
1946 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001947
Damien Miller95def091999-11-25 00:26:21 +11001948 /* Declare which ciphers we support. */
Damien Miller874d77b2000-10-14 16:23:11 +11001949 packet_put_int(cipher_mask_ssh1(0));
Damien Miller95def091999-11-25 00:26:21 +11001950
1951 /* Declare supported authentication types. */
1952 auth_mask = 0;
Damien Miller95def091999-11-25 00:26:21 +11001953 if (options.rhosts_rsa_authentication)
1954 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1955 if (options.rsa_authentication)
1956 auth_mask |= 1 << SSH_AUTH_RSA;
Ben Lindstrom551ea372001-06-05 18:56:16 +00001957 if (options.challenge_response_authentication == 1)
Damien Miller95def091999-11-25 00:26:21 +11001958 auth_mask |= 1 << SSH_AUTH_TIS;
Damien Miller95def091999-11-25 00:26:21 +11001959 if (options.password_authentication)
1960 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1961 packet_put_int(auth_mask);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001962
Damien Miller95def091999-11-25 00:26:21 +11001963 /* Send the packet and wait for it to be sent. */
1964 packet_send();
1965 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001966
Damien Miller0bc1bd82000-11-13 22:57:25 +11001967 debug("Sent %d bit server key and %d bit host key.",
1968 BN_num_bits(sensitive_data.server_key->rsa->n),
1969 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001970
Damien Miller95def091999-11-25 00:26:21 +11001971 /* Read clients reply (cipher type and session key). */
Damien Millerdff50992002-01-22 23:16:32 +11001972 packet_read_expect(SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001973
Damien Miller50945fa1999-12-09 10:31:37 +11001974 /* Get cipher type and check whether we accept this. */
Damien Miller95def091999-11-25 00:26:21 +11001975 cipher_type = packet_get_char();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001976
Damien Miller874d77b2000-10-14 16:23:11 +11001977 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
Damien Miller50945fa1999-12-09 10:31:37 +11001978 packet_disconnect("Warning: client selects unsupported cipher.");
1979
Damien Miller95def091999-11-25 00:26:21 +11001980 /* Get check bytes from the packet. These must match those we
1981 sent earlier with the public key packet. */
1982 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001983 if (cookie[i] != packet_get_char())
Damien Miller95def091999-11-25 00:26:21 +11001984 packet_disconnect("IP Spoofing check bytes do not match.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001985
Damien Miller95def091999-11-25 00:26:21 +11001986 debug("Encryption type: %.200s", cipher_name(cipher_type));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001987
Damien Miller95def091999-11-25 00:26:21 +11001988 /* Get the encrypted integer. */
Damien Millerda755162002-01-22 23:09:22 +11001989 if ((session_key_int = BN_new()) == NULL)
1990 fatal("do_ssh1_kex: BN_new failed");
Damien Millerd432ccf2002-01-22 23:14:44 +11001991 packet_get_bignum(session_key_int);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001992
Damien Miller95def091999-11-25 00:26:21 +11001993 protocol_flags = packet_get_int();
1994 packet_set_protocol_flags(protocol_flags);
Damien Miller48b03fc2002-01-22 23:11:40 +11001995 packet_check_eom();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001996
Ben Lindstromabcb1452002-03-22 01:10:21 +00001997 /* Decrypt session_key_int using host/server keys */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001998 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1999
Damien Miller5428f641999-11-25 11:54:57 +11002000 /*
2001 * Extract session key from the decrypted integer. The key is in the
2002 * least significant 256 bits of the integer; the first byte of the
2003 * key is in the highest bits.
2004 */
Damien Miller7650bc62001-01-30 09:27:26 +11002005 if (!rsafail) {
2006 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
2007 len = BN_num_bytes(session_key_int);
Damien Millereccb9de2005-06-17 12:59:34 +10002008 if (len < 0 || (u_int)len > sizeof(session_key)) {
Damien Miller7650bc62001-01-30 09:27:26 +11002009 error("do_connection: bad session key len from %s: "
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00002010 "session_key_int %d > sizeof(session_key) %lu",
2011 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
Damien Miller7650bc62001-01-30 09:27:26 +11002012 rsafail++;
2013 } else {
2014 memset(session_key, 0, sizeof(session_key));
2015 BN_bn2bin(session_key_int,
2016 session_key + sizeof(session_key) - len);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002017
Darren Tuckere14e0052004-05-13 16:30:44 +10002018 derive_ssh1_session_id(
Darren Tuckerfc959702004-07-17 16:12:08 +10002019 sensitive_data.ssh1_host_key->rsa->n,
Darren Tuckere14e0052004-05-13 16:30:44 +10002020 sensitive_data.server_key->rsa->n,
2021 cookie, session_id);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002022 /*
2023 * Xor the first 16 bytes of the session key with the
2024 * session id.
2025 */
2026 for (i = 0; i < 16; i++)
2027 session_key[i] ^= session_id[i];
Damien Miller7650bc62001-01-30 09:27:26 +11002028 }
2029 }
2030 if (rsafail) {
Ben Lindstromeb648a72001-03-05 06:00:29 +00002031 int bytes = BN_num_bytes(session_key_int);
Ben Lindstrom13c5d3b2002-02-26 18:00:48 +00002032 u_char *buf = xmalloc(bytes);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002033 MD5_CTX md;
2034
Damien Miller996acd22003-04-09 20:59:48 +10002035 logit("do_connection: generating a fake encryption key");
Ben Lindstromeb648a72001-03-05 06:00:29 +00002036 BN_bn2bin(session_key_int, buf);
2037 MD5_Init(&md);
2038 MD5_Update(&md, buf, bytes);
2039 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
2040 MD5_Final(session_key, &md);
2041 MD5_Init(&md);
2042 MD5_Update(&md, session_key, 16);
2043 MD5_Update(&md, buf, bytes);
2044 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
2045 MD5_Final(session_key + 16, &md);
2046 memset(buf, 0, bytes);
2047 xfree(buf);
Ben Lindstrom941ac822001-03-05 06:25:23 +00002048 for (i = 0; i < 16; i++)
2049 session_id[i] = session_key[i] ^ session_key[i + 16];
Damien Miller7650bc62001-01-30 09:27:26 +11002050 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002051 /* Destroy the private and public keys. No longer. */
Damien Miller3a5b0232002-03-13 13:19:42 +11002052 destroy_sensitive_data();
Ben Lindstromeb648a72001-03-05 06:00:29 +00002053
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002054 if (use_privsep)
2055 mm_ssh1_session_id(session_id);
2056
Damien Miller396691a2000-01-20 22:44:08 +11002057 /* Destroy the decrypted integer. It is no longer needed. */
2058 BN_clear_free(session_key_int);
2059
Damien Miller95def091999-11-25 00:26:21 +11002060 /* Set the session key. From this on all communications will be encrypted. */
2061 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002062
Damien Miller95def091999-11-25 00:26:21 +11002063 /* Destroy our copy of the session key. It is no longer needed. */
2064 memset(session_key, 0, sizeof(session_key));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002065
Damien Miller95def091999-11-25 00:26:21 +11002066 debug("Received session key; encryption turned on.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002067
Ben Lindstromf666fec2002-06-06 19:51:58 +00002068 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
Damien Miller95def091999-11-25 00:26:21 +11002069 packet_start(SSH_SMSG_SUCCESS);
2070 packet_send();
2071 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002072}
Damien Millerefb4afe2000-04-12 18:45:05 +10002073
2074/*
2075 * SSH2 key exchange: diffie-hellman-group1-sha1
2076 */
Ben Lindstrombba81212001-06-25 05:01:22 +00002077static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00002078do_ssh2_kex(void)
Damien Millerefb4afe2000-04-12 18:45:05 +10002079{
Damien Millerefb4afe2000-04-12 18:45:05 +10002080 Kex *kex;
Damien Millerefb4afe2000-04-12 18:45:05 +10002081
Damien Miller78928792000-04-12 20:17:38 +10002082 if (options.ciphers != NULL) {
Damien Miller4af51302000-04-16 11:18:38 +10002083 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
Damien Miller78928792000-04-12 20:17:38 +10002084 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
2085 }
Damien Millera0ff4662001-03-30 10:49:35 +10002086 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
2087 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
2088 myproposal[PROPOSAL_ENC_ALGS_STOC] =
2089 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
2090
Ben Lindstrom06b33aa2001-02-15 03:01:59 +00002091 if (options.macs != NULL) {
2092 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2093 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2094 }
Damien Miller9786e6e2005-07-26 21:54:56 +10002095 if (options.compression == COMP_NONE) {
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002096 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2097 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
Damien Miller9786e6e2005-07-26 21:54:56 +10002098 } else if (options.compression == COMP_DELAYED) {
2099 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2100 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002101 }
Damien Millerf0b15df2006-03-26 13:59:20 +11002102
Damien Miller0bc1bd82000-11-13 22:57:25 +11002103 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
2104
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002105 /* start key exchange */
Ben Lindstrom238abf62001-04-04 17:52:53 +00002106 kex = kex_setup(myproposal);
Damien Miller8e7fb332003-02-24 12:03:03 +11002107 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
Damien Millerf675fc42004-06-15 10:30:09 +10002108 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
Damien Miller8e7fb332003-02-24 12:03:03 +11002109 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
Damien Millera63128d2006-03-15 12:08:28 +11002110 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002111 kex->server = 1;
2112 kex->client_version_string=client_version_string;
2113 kex->server_version_string=server_version_string;
2114 kex->load_host_key=&get_hostkey_by_type;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002115 kex->host_key_index=&get_hostkey_index;
Damien Millerefb4afe2000-04-12 18:45:05 +10002116
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002117 xxx_kex = kex;
2118
Ben Lindstrombe2cc432001-04-04 23:46:07 +00002119 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
Damien Miller874d77b2000-10-14 16:23:11 +11002120
Ben Lindstrom2d90e002001-04-04 02:00:54 +00002121 session_id2 = kex->session_id;
2122 session_id2_len = kex->session_id_len;
2123
Damien Miller874d77b2000-10-14 16:23:11 +11002124#ifdef DEBUG_KEXDH
2125 /* send 1st encrypted/maced/compressed message */
2126 packet_start(SSH2_MSG_IGNORE);
2127 packet_put_cstring("markus");
2128 packet_send();
2129 packet_write_wait();
2130#endif
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002131 debug("KEX done");
Damien Millerefb4afe2000-04-12 18:45:05 +10002132}
Darren Tucker3e33cec2003-10-02 16:12:36 +10002133
2134/* server specific fatal cleanup */
2135void
2136cleanup_exit(int i)
2137{
2138 if (the_authctxt)
2139 do_cleanup(the_authctxt);
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002140#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11002141 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
2142 if (!use_privsep || mm_is_monitor())
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002143 audit_event(SSH_CONNECTION_ABANDON);
Darren Tucker269a1ea2005-02-03 00:20:53 +11002144#endif
Darren Tucker3e33cec2003-10-02 16:12:36 +10002145 _exit(i);
2146}