blob: 27c38ba53168fa3dda6e2a3cbd3e72533f6c5c35 [file] [log] [blame]
Darren Tucker58911162008-01-01 20:33:09 +11001/* $OpenBSD: sshd.c,v 1.353 2007/12/31 15:27:04 dtucker Exp $ */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002/*
Damien Miller95def091999-11-25 00:26:21 +11003 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
Damien Millere4340be2000-09-16 13:29:08 +11006 * This program is the ssh daemon. It listens for connections from clients,
7 * and performs authentication, executes use commands or shell, and forwards
Damien Miller95def091999-11-25 00:26:21 +11008 * information to/from the application to the user client over an encrypted
Damien Millere4340be2000-09-16 13:29:08 +11009 * connection. This can also handle forwarding of X11, TCP/IP, and
10 * authentication agent connections.
Damien Millerefb4afe2000-04-12 18:45:05 +100011 *
Damien Millere4340be2000-09-16 13:29:08 +110012 * As far as I am concerned, the code I have written for this software
13 * can be used freely for any purpose. Any derived versions of this
14 * software must be clearly marked as such, and if the derived work is
15 * incompatible with the protocol description in the RFC file, it must be
16 * called by a name other than "ssh" or "Secure Shell".
17 *
18 * SSH2 implementation:
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000019 * Privilege Separation:
Damien Millere4340be2000-09-16 13:29:08 +110020 *
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000021 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
22 * Copyright (c) 2002 Niels Provos. All rights reserved.
Damien Millere4340be2000-09-16 13:29:08 +110023 *
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
26 * are met:
27 * 1. Redistributions of source code must retain the above copyright
28 * notice, this list of conditions and the following disclaimer.
29 * 2. Redistributions in binary form must reproduce the above copyright
30 * notice, this list of conditions and the following disclaimer in the
31 * documentation and/or other materials provided with the distribution.
32 *
33 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
34 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
36 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
37 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
39 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
40 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
41 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
42 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Miller95def091999-11-25 00:26:21 +110043 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100044
45#include "includes.h"
Damien Miller17e91c02006-03-15 11:28:34 +110046
Damien Miller9cf6d072006-03-15 11:29:24 +110047#include <sys/types.h>
Damien Millerd7834352006-08-05 12:39:39 +100048#include <sys/ioctl.h>
49#include <sys/socket.h>
Damien Millerf17883e2006-03-15 11:45:54 +110050#ifdef HAVE_SYS_STAT_H
51# include <sys/stat.h>
52#endif
Damien Miller9aec9192006-08-05 10:57:45 +100053#ifdef HAVE_SYS_TIME_H
54# include <sys/time.h>
55#endif
Damien Millerd7834352006-08-05 12:39:39 +100056#include "openbsd-compat/sys-tree.h"
Damien Miller9cf6d072006-03-15 11:29:24 +110057#include <sys/wait.h>
Damien Miller03e20032006-03-15 11:16:59 +110058
Darren Tucker39972492006-07-12 22:22:46 +100059#include <errno.h>
Damien Miller57cf6382006-07-10 21:13:46 +100060#include <fcntl.h>
Damien Millerb8fe89c2006-07-24 14:51:00 +100061#include <netdb.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110062#ifdef HAVE_PATHS_H
Damien Miller03e20032006-03-15 11:16:59 +110063#include <paths.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110064#endif
Damien Millera1738e42006-07-10 21:33:04 +100065#include <grp.h>
Damien Miller9f2abc42006-07-10 20:53:08 +100066#include <pwd.h>
Damien Miller6ff3cad2006-03-15 11:52:09 +110067#include <signal.h>
Damien Millerded319c2006-09-01 15:38:36 +100068#include <stdarg.h>
Damien Millera7a73ee2006-08-05 11:37:59 +100069#include <stdio.h>
Damien Millere7a1e5c2006-08-05 11:34:19 +100070#include <stdlib.h>
Damien Millere3476ed2006-07-24 14:13:33 +100071#include <string.h>
Damien Miller75bb6642006-08-05 14:07:20 +100072#include <unistd.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100073
Ben Lindstrom226cfa02001-01-22 05:34:40 +000074#include <openssl/dh.h>
75#include <openssl/bn.h>
Damien Miller6a47f302002-02-13 13:55:06 +110076#include <openssl/md5.h>
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000077#include <openssl/rand.h>
Kevin Steves0ea1d9d2002-04-25 18:17:04 +000078#ifdef HAVE_SECUREWARE
79#include <sys/security.h>
80#include <prot.h>
81#endif
Ben Lindstrom226cfa02001-01-22 05:34:40 +000082
Damien Millerd7834352006-08-05 12:39:39 +100083#include "xmalloc.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000084#include "ssh.h"
85#include "ssh1.h"
86#include "ssh2.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100087#include "rsa.h"
Ben Lindstromd95c09c2001-02-18 19:13:33 +000088#include "sshpty.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100089#include "packet.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000090#include "log.h"
Damien Millerd7834352006-08-05 12:39:39 +100091#include "buffer.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100092#include "servconf.h"
93#include "uidswap.h"
94#include "compat.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000095#include "cipher.h"
Damien Millerb38eff82000-04-01 11:09:21 +100096#include "key.h"
Damien Millerd7834352006-08-05 12:39:39 +100097#include "kex.h"
Damien Miller874d77b2000-10-14 16:23:11 +110098#include "dh.h"
Damien Millerefb4afe2000-04-12 18:45:05 +100099#include "myproposal.h"
Damien Millereba71ba2000-04-29 23:57:08 +1000100#include "authfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000101#include "pathnames.h"
102#include "atomicio.h"
103#include "canohost.h"
Damien Millerd7834352006-08-05 12:39:39 +1000104#include "hostfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000105#include "auth.h"
106#include "misc.h"
Darren Tucker645ab752004-06-25 13:33:20 +1000107#include "msg.h"
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +0000108#include "dispatch.h"
Ben Lindstrom1bae4042001-10-03 17:46:39 +0000109#include "channels.h"
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +0000110#include "session.h"
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000111#include "monitor_mm.h"
112#include "monitor.h"
Damien Millerd7834352006-08-05 12:39:39 +1000113#ifdef GSSAPI
114#include "ssh-gss.h"
115#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000116#include "monitor_wrap.h"
117#include "monitor_fdpass.h"
Damien Millerb7576772006-07-10 20:23:39 +1000118#include "version.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000119
120#ifdef LIBWRAP
121#include <tcpd.h>
122#include <syslog.h>
123int allow_severity = LOG_INFO;
124int deny_severity = LOG_WARNING;
125#endif /* LIBWRAP */
126
127#ifndef O_NOCTTY
128#define O_NOCTTY 0
129#endif
130
Damien Miller035a5b42004-06-26 08:16:31 +1000131/* Re-exec fds */
132#define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
133#define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
134#define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
135#define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
136
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000137extern char *__progname;
Ben Lindstrom49a79c02000-11-17 03:47:20 +0000138
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000139/* Server configuration options. */
140ServerOptions options;
141
142/* Name of the server configuration file. */
Ben Lindstrom226cfa02001-01-22 05:34:40 +0000143char *config_file_name = _PATH_SERVER_CONFIG_FILE;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000144
Damien Miller4af51302000-04-16 11:18:38 +1000145/*
Damien Miller95def091999-11-25 00:26:21 +1100146 * Debug mode flag. This can be set on the command line. If debug
147 * mode is enabled, extra debugging output will be sent to the system
148 * log, the daemon will not go to background, and will exit after processing
149 * the first connection.
150 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000151int debug_flag = 0;
152
Ben Lindstrom794325a2001-08-06 21:09:07 +0000153/* Flag indicating that the daemon should only test the configuration and keys. */
154int test_flag = 0;
155
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000156/* Flag indicating that the daemon is being started from inetd. */
157int inetd_flag = 0;
158
Ben Lindstromc72745a2000-12-02 19:03:54 +0000159/* Flag indicating that sshd should not detach and become a daemon. */
160int no_daemon_flag = 0;
161
Damien Miller5ce662a1999-11-11 17:57:39 +1100162/* debug goes to stderr unless inetd_flag is set */
163int log_stderr = 0;
164
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000165/* Saved arguments to main(). */
166char **saved_argv;
Damien Millerb8c656e2000-06-28 15:22:41 +1000167int saved_argc;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000168
Darren Tucker645ab752004-06-25 13:33:20 +1000169/* re-exec */
170int rexeced_flag = 0;
171int rexec_flag = 1;
172int rexec_argc = 0;
173char **rexec_argv;
174
Damien Miller5428f641999-11-25 11:54:57 +1100175/*
Damien Miller34132e52000-01-14 15:45:46 +1100176 * The sockets that the server is listening; this is used in the SIGHUP
177 * signal handler.
Damien Miller5428f641999-11-25 11:54:57 +1100178 */
Damien Miller34132e52000-01-14 15:45:46 +1100179#define MAX_LISTEN_SOCKS 16
180int listen_socks[MAX_LISTEN_SOCKS];
181int num_listen_socks = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000182
Damien Miller5428f641999-11-25 11:54:57 +1100183/*
184 * the client's version string, passed by sshd2 in compat mode. if != NULL,
185 * sshd will skip the version-number exchange
186 */
Damien Miller95def091999-11-25 00:26:21 +1100187char *client_version_string = NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000188char *server_version_string = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000189
Ben Lindstrom8ac91062001-04-04 17:57:54 +0000190/* for rekeying XXX fixme */
191Kex *xxx_kex;
192
Damien Miller5428f641999-11-25 11:54:57 +1100193/*
194 * Any really sensitive data in the application is contained in this
195 * structure. The idea is that this structure could be locked into memory so
196 * that the pages do not get written into swap. However, there are some
197 * problems. The private key contains BIGNUMs, and we do not (in principle)
198 * have access to the internals of them, and locking just the structure is
199 * not very useful. Currently, memory locking is not implemented.
200 */
Damien Miller95def091999-11-25 00:26:21 +1100201struct {
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000202 Key *server_key; /* ephemeral server key */
Damien Miller0bc1bd82000-11-13 22:57:25 +1100203 Key *ssh1_host_key; /* ssh1 host key */
204 Key **host_keys; /* all private host keys */
205 int have_ssh1_key;
206 int have_ssh2_key;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000207 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000208} sensitive_data;
209
Damien Miller5428f641999-11-25 11:54:57 +1100210/*
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000211 * Flag indicating whether the RSA server key needs to be regenerated.
212 * Is set in the SIGALRM handler and cleared when the key is regenerated.
Damien Miller5428f641999-11-25 11:54:57 +1100213 */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000214static volatile sig_atomic_t key_do_regen = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000215
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000216/* This is set to true when a signal is received. */
Ben Lindstrom5e71c542001-12-06 16:48:14 +0000217static volatile sig_atomic_t received_sighup = 0;
218static volatile sig_atomic_t received_sigterm = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000219
Damien Millerb38eff82000-04-01 11:09:21 +1000220/* session identifier, used by RSA-auth */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000221u_char session_id[16];
Damien Millerb38eff82000-04-01 11:09:21 +1000222
Damien Millereba71ba2000-04-29 23:57:08 +1000223/* same for ssh2 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000224u_char *session_id2 = NULL;
Darren Tucker502d3842003-06-28 12:38:01 +1000225u_int session_id2_len = 0;
Damien Millereba71ba2000-04-29 23:57:08 +1000226
Damien Miller942da032000-08-18 13:59:06 +1000227/* record remote hostname or ip */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000228u_int utmp_len = MAXHOSTNAMELEN;
Damien Miller942da032000-08-18 13:59:06 +1000229
Ben Lindstromd84df982001-12-06 16:35:40 +0000230/* options.max_startup sized array of fd ints */
231int *startup_pipes = NULL;
232int startup_pipe; /* in child */
233
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000234/* variables used for privilege separation */
Darren Tucker45150472006-07-12 22:34:17 +1000235int use_privsep = -1;
Darren Tuckera8be9e22004-02-06 16:40:27 +1100236struct monitor *pmonitor = NULL;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000237
Darren Tucker3e33cec2003-10-02 16:12:36 +1000238/* global authentication context */
239Authctxt *the_authctxt = NULL;
240
Darren Tucker45150472006-07-12 22:34:17 +1000241/* sshd_config buffer */
242Buffer cfg;
243
Darren Tucker09991742004-07-17 17:05:14 +1000244/* message to be displayed after login */
245Buffer loginmsg;
246
Damien Miller6433df02006-09-07 10:36:43 +1000247/* Unprivileged user */
248struct passwd *privsep_pw = NULL;
249
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000250/* Prototypes for various functions defined later in this file. */
Ben Lindstrombba81212001-06-25 05:01:22 +0000251void destroy_sensitive_data(void);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000252void demote_sensitive_data(void);
Damien Miller98c7ad62000-03-09 21:27:49 +1100253
Ben Lindstrombba81212001-06-25 05:01:22 +0000254static void do_ssh1_kex(void);
255static void do_ssh2_kex(void);
Damien Miller874d77b2000-10-14 16:23:11 +1100256
Damien Miller98c7ad62000-03-09 21:27:49 +1100257/*
Damien Miller34132e52000-01-14 15:45:46 +1100258 * Close all listening sockets
259 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000260static void
Damien Miller34132e52000-01-14 15:45:46 +1100261close_listen_socks(void)
262{
263 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000264
Damien Miller34132e52000-01-14 15:45:46 +1100265 for (i = 0; i < num_listen_socks; i++)
266 close(listen_socks[i]);
267 num_listen_socks = -1;
268}
269
Ben Lindstromd84df982001-12-06 16:35:40 +0000270static void
271close_startup_pipes(void)
272{
273 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000274
Ben Lindstromd84df982001-12-06 16:35:40 +0000275 if (startup_pipes)
276 for (i = 0; i < options.max_startups; i++)
277 if (startup_pipes[i] != -1)
278 close(startup_pipes[i]);
279}
280
Damien Miller34132e52000-01-14 15:45:46 +1100281/*
Damien Miller95def091999-11-25 00:26:21 +1100282 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
283 * the effect is to reread the configuration file (and to regenerate
284 * the server key).
285 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100286
287/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000288static void
Damien Miller95def091999-11-25 00:26:21 +1100289sighup_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000290{
Ben Lindstrom07958482001-12-06 16:19:01 +0000291 int save_errno = errno;
292
Damien Miller95def091999-11-25 00:26:21 +1100293 received_sighup = 1;
294 signal(SIGHUP, sighup_handler);
Ben Lindstrom07958482001-12-06 16:19:01 +0000295 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000296}
297
Damien Miller95def091999-11-25 00:26:21 +1100298/*
299 * Called from the main program after receiving SIGHUP.
300 * Restarts the server.
301 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000302static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000303sighup_restart(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000304{
Damien Miller996acd22003-04-09 20:59:48 +1000305 logit("Received SIGHUP; restarting.");
Damien Miller34132e52000-01-14 15:45:46 +1100306 close_listen_socks();
Ben Lindstromd84df982001-12-06 16:35:40 +0000307 close_startup_pipes();
Darren Tuckered623962007-02-25 20:37:21 +1100308 alarm(0); /* alarm timer persists across exec */
Damien Miller95def091999-11-25 00:26:21 +1100309 execv(saved_argv[0], saved_argv);
Damien Miller996acd22003-04-09 20:59:48 +1000310 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
Ben Lindstrom822b6342002-06-23 21:38:49 +0000311 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100312 exit(1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000313}
314
Damien Miller95def091999-11-25 00:26:21 +1100315/*
316 * Generic signal handler for terminating signals in the master daemon.
Damien Miller95def091999-11-25 00:26:21 +1100317 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100318/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000319static void
Damien Miller95def091999-11-25 00:26:21 +1100320sigterm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000321{
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000322 received_sigterm = sig;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000323}
324
Damien Miller95def091999-11-25 00:26:21 +1100325/*
326 * SIGCHLD handler. This is called whenever a child dies. This will then
Ben Lindstromec46e0b2001-06-09 01:27:31 +0000327 * reap any zombies left by exited children.
Damien Miller95def091999-11-25 00:26:21 +1100328 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100329/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000330static void
Damien Miller95def091999-11-25 00:26:21 +1100331main_sigchld_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000332{
Damien Miller95def091999-11-25 00:26:21 +1100333 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000334 pid_t pid;
Damien Miller95def091999-11-25 00:26:21 +1100335 int status;
Damien Miller431f66b1999-11-21 18:31:57 +1100336
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000337 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
338 (pid < 0 && errno == EINTR))
Damien Miller95def091999-11-25 00:26:21 +1100339 ;
Damien Miller431f66b1999-11-21 18:31:57 +1100340
Damien Miller95def091999-11-25 00:26:21 +1100341 signal(SIGCHLD, main_sigchld_handler);
342 errno = save_errno;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000343}
344
Damien Miller95def091999-11-25 00:26:21 +1100345/*
346 * Signal handler for the alarm after the login grace period has expired.
347 */
Damien Millerf0b15df2006-03-26 13:59:20 +1100348/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000349static void
Damien Miller95def091999-11-25 00:26:21 +1100350grace_alarm_handler(int sig)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000351{
Darren Tuckera8be9e22004-02-06 16:40:27 +1100352 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
353 kill(pmonitor->m_pid, SIGALRM);
354
Damien Miller95def091999-11-25 00:26:21 +1100355 /* Log error and exit. */
Damien Miller99a648e2006-08-19 00:32:20 +1000356 sigdie("Timeout before authentication for %s", get_remote_ipaddr());
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000357}
358
Damien Miller95def091999-11-25 00:26:21 +1100359/*
Damien Miller95def091999-11-25 00:26:21 +1100360 * Signal handler for the key regeneration alarm. Note that this
361 * alarm only occurs in the daemon waiting for connections, and it does not
362 * do anything with the private key or random state before forking.
363 * Thus there should be no concurrency control/asynchronous execution
364 * problems.
365 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000366static void
Ben Lindstromca42d5f2001-03-09 18:25:32 +0000367generate_ephemeral_server_key(void)
Damien Miller0bc1bd82000-11-13 22:57:25 +1100368{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000369 u_int32_t rnd = 0;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000370 int i;
371
Ben Lindstroma3700052001-04-05 23:26:32 +0000372 verbose("Generating %s%d bit RSA key.",
Damien Millerff75ac42001-03-30 10:50:32 +1000373 sensitive_data.server_key ? "new " : "", options.server_key_bits);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100374 if (sensitive_data.server_key != NULL)
375 key_free(sensitive_data.server_key);
Ben Lindstroma3700052001-04-05 23:26:32 +0000376 sensitive_data.server_key = key_generate(KEY_RSA1,
Damien Millerff75ac42001-03-30 10:50:32 +1000377 options.server_key_bits);
378 verbose("RSA key generation complete.");
Ben Lindstromeb648a72001-03-05 06:00:29 +0000379
380 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
381 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000382 rnd = arc4random();
383 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
384 rnd >>= 8;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000385 }
386 arc4random_stir();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100387}
Ben Lindstrom2f959b42001-01-11 06:20:23 +0000388
Damien Millerf0b15df2006-03-26 13:59:20 +1100389/*ARGSUSED*/
Ben Lindstrombba81212001-06-25 05:01:22 +0000390static void
Damien Miller95def091999-11-25 00:26:21 +1100391key_regeneration_alarm(int sig)
392{
393 int save_errno = errno;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000394
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000395 signal(SIGALRM, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +1100396 errno = save_errno;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000397 key_do_regen = 1;
Damien Miller95def091999-11-25 00:26:21 +1100398}
399
Ben Lindstrombba81212001-06-25 05:01:22 +0000400static void
Damien Millerb38eff82000-04-01 11:09:21 +1000401sshd_exchange_identification(int sock_in, int sock_out)
402{
Damien Millereccb9de2005-06-17 12:59:34 +1000403 u_int i;
404 int mismatch;
Damien Millerb38eff82000-04-01 11:09:21 +1000405 int remote_major, remote_minor;
Damien Miller78928792000-04-12 20:17:38 +1000406 int major, minor;
Damien Millerb38eff82000-04-01 11:09:21 +1000407 char *s;
408 char buf[256]; /* Must not be larger than remote_version. */
409 char remote_version[256]; /* Must be at least as big as buf. */
410
Damien Miller78928792000-04-12 20:17:38 +1000411 if ((options.protocol & SSH_PROTO_1) &&
412 (options.protocol & SSH_PROTO_2)) {
413 major = PROTOCOL_MAJOR_1;
414 minor = 99;
415 } else if (options.protocol & SSH_PROTO_2) {
416 major = PROTOCOL_MAJOR_2;
417 minor = PROTOCOL_MINOR_2;
418 } else {
419 major = PROTOCOL_MAJOR_1;
420 minor = PROTOCOL_MINOR_1;
421 }
422 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
Damien Millerb38eff82000-04-01 11:09:21 +1000423 server_version_string = xstrdup(buf);
424
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000425 /* Send our protocol version identification. */
426 if (atomicio(vwrite, sock_out, server_version_string,
427 strlen(server_version_string))
428 != strlen(server_version_string)) {
429 logit("Could not write ident string to %s", get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000430 cleanup_exit(255);
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000431 }
432
433 /* Read other sides version identification. */
434 memset(buf, 0, sizeof(buf));
435 for (i = 0; i < sizeof(buf) - 1; i++) {
436 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
437 logit("Did not receive identification string from %s",
438 get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000439 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000440 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000441 if (buf[i] == '\r') {
442 buf[i] = 0;
443 /* Kludge for F-Secure Macintosh < 1.0.2 */
444 if (i == 12 &&
445 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
Damien Millerb38eff82000-04-01 11:09:21 +1000446 break;
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000447 continue;
Damien Millerb38eff82000-04-01 11:09:21 +1000448 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000449 if (buf[i] == '\n') {
450 buf[i] = 0;
451 break;
452 }
Damien Millerb38eff82000-04-01 11:09:21 +1000453 }
Darren Tuckerfe0078a2003-07-19 19:52:28 +1000454 buf[sizeof(buf) - 1] = 0;
455 client_version_string = xstrdup(buf);
Damien Millerb38eff82000-04-01 11:09:21 +1000456
457 /*
458 * Check that the versions match. In future this might accept
459 * several versions and set appropriate flags to handle them.
460 */
461 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
462 &remote_major, &remote_minor, remote_version) != 3) {
Damien Miller4af51302000-04-16 11:18:38 +1000463 s = "Protocol mismatch.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000464 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Millerb38eff82000-04-01 11:09:21 +1000465 close(sock_in);
466 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000467 logit("Bad protocol version identification '%.100s' from %s",
Damien Millerb38eff82000-04-01 11:09:21 +1000468 client_version_string, get_remote_ipaddr());
Darren Tucker3e33cec2003-10-02 16:12:36 +1000469 cleanup_exit(255);
Damien Millerb38eff82000-04-01 11:09:21 +1000470 }
471 debug("Client protocol version %d.%d; client software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100472 remote_major, remote_minor, remote_version);
Damien Millerb38eff82000-04-01 11:09:21 +1000473
Damien Millerefb4afe2000-04-12 18:45:05 +1000474 compat_datafellows(remote_version);
475
Damien Millere9264972002-09-30 11:59:21 +1000476 if (datafellows & SSH_BUG_PROBE) {
Damien Miller996acd22003-04-09 20:59:48 +1000477 logit("probed from %s with %s. Don't panic.",
Damien Millere9264972002-09-30 11:59:21 +1000478 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000479 cleanup_exit(255);
Damien Millere9264972002-09-30 11:59:21 +1000480 }
481
Damien Miller27dbe6f2001-03-19 22:36:20 +1100482 if (datafellows & SSH_BUG_SCANNER) {
Damien Miller996acd22003-04-09 20:59:48 +1000483 logit("scanned from %s with %s. Don't panic.",
Damien Miller27dbe6f2001-03-19 22:36:20 +1100484 get_remote_ipaddr(), client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000485 cleanup_exit(255);
Damien Miller27dbe6f2001-03-19 22:36:20 +1100486 }
487
Damien Miller78928792000-04-12 20:17:38 +1000488 mismatch = 0;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000489 switch (remote_major) {
Damien Millerb38eff82000-04-01 11:09:21 +1000490 case 1:
Damien Millereba71ba2000-04-29 23:57:08 +1000491 if (remote_minor == 99) {
492 if (options.protocol & SSH_PROTO_2)
493 enable_compat20();
494 else
495 mismatch = 1;
496 break;
497 }
Damien Miller78928792000-04-12 20:17:38 +1000498 if (!(options.protocol & SSH_PROTO_1)) {
499 mismatch = 1;
500 break;
501 }
Damien Millerb38eff82000-04-01 11:09:21 +1000502 if (remote_minor < 3) {
Damien Miller37023962000-07-11 17:31:38 +1000503 packet_disconnect("Your ssh version is too old and "
Damien Millerb38eff82000-04-01 11:09:21 +1000504 "is no longer supported. Please install a newer version.");
505 } else if (remote_minor == 3) {
506 /* note that this disables agent-forwarding */
507 enable_compat13();
508 }
Damien Miller78928792000-04-12 20:17:38 +1000509 break;
Damien Millerefb4afe2000-04-12 18:45:05 +1000510 case 2:
Damien Miller78928792000-04-12 20:17:38 +1000511 if (options.protocol & SSH_PROTO_2) {
Damien Millerefb4afe2000-04-12 18:45:05 +1000512 enable_compat20();
513 break;
514 }
515 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000516 default:
Damien Miller78928792000-04-12 20:17:38 +1000517 mismatch = 1;
Damien Millerb38eff82000-04-01 11:09:21 +1000518 break;
519 }
Damien Millerefb4afe2000-04-12 18:45:05 +1000520 chop(server_version_string);
Damien Miller78928792000-04-12 20:17:38 +1000521 debug("Local version string %.200s", server_version_string);
522
523 if (mismatch) {
524 s = "Protocol major versions differ.\n";
Darren Tucker9f63f222003-07-03 13:46:56 +1000525 (void) atomicio(vwrite, sock_out, s, strlen(s));
Damien Miller78928792000-04-12 20:17:38 +1000526 close(sock_in);
527 close(sock_out);
Damien Miller996acd22003-04-09 20:59:48 +1000528 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
Damien Miller78928792000-04-12 20:17:38 +1000529 get_remote_ipaddr(),
530 server_version_string, client_version_string);
Darren Tucker3e33cec2003-10-02 16:12:36 +1000531 cleanup_exit(255);
Damien Miller78928792000-04-12 20:17:38 +1000532 }
Damien Millereba71ba2000-04-29 23:57:08 +1000533}
534
Damien Miller0bc1bd82000-11-13 22:57:25 +1100535/* Destroy the host and server keys. They will no longer be needed. */
Damien Millereba71ba2000-04-29 23:57:08 +1000536void
537destroy_sensitive_data(void)
538{
Damien Miller0bc1bd82000-11-13 22:57:25 +1100539 int i;
540
541 if (sensitive_data.server_key) {
542 key_free(sensitive_data.server_key);
543 sensitive_data.server_key = NULL;
544 }
Damien Miller9f0f5c62001-12-21 14:45:46 +1100545 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100546 if (sensitive_data.host_keys[i]) {
547 key_free(sensitive_data.host_keys[i]);
548 sensitive_data.host_keys[i] = NULL;
549 }
550 }
551 sensitive_data.ssh1_host_key = NULL;
Ben Lindstromeb648a72001-03-05 06:00:29 +0000552 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
Damien Miller0bc1bd82000-11-13 22:57:25 +1100553}
Damien Miller0bc1bd82000-11-13 22:57:25 +1100554
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000555/* Demote private to public keys for network child */
556void
557demote_sensitive_data(void)
558{
559 Key *tmp;
560 int i;
561
562 if (sensitive_data.server_key) {
563 tmp = key_demote(sensitive_data.server_key);
564 key_free(sensitive_data.server_key);
565 sensitive_data.server_key = tmp;
566 }
567
568 for (i = 0; i < options.num_host_key_files; i++) {
569 if (sensitive_data.host_keys[i]) {
570 tmp = key_demote(sensitive_data.host_keys[i]);
571 key_free(sensitive_data.host_keys[i]);
572 sensitive_data.host_keys[i] = tmp;
573 if (tmp->type == KEY_RSA1)
574 sensitive_data.ssh1_host_key = tmp;
575 }
576 }
577
578 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
579}
580
Ben Lindstrom08105192002-03-22 02:50:06 +0000581static void
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000582privsep_preauth_child(void)
583{
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000584 u_int32_t rnd[256];
Ben Lindstrom810af962002-07-04 00:11:40 +0000585 gid_t gidset[1];
Ben Lindstrom822b6342002-06-23 21:38:49 +0000586 int i;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000587
588 /* Enable challenge-response authentication for privilege separation */
589 privsep_challenge_enable();
590
591 for (i = 0; i < 256; i++)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +0000592 rnd[i] = arc4random();
593 RAND_seed(rnd, sizeof(rnd));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000594
595 /* Demote the private keys to public keys. */
596 demote_sensitive_data();
597
Ben Lindstroma962c2f2002-07-04 00:14:17 +0000598 /* Change our root directory */
Ben Lindstrom7a7edf72002-03-22 02:42:37 +0000599 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
600 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
601 strerror(errno));
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000602 if (chdir("/") == -1)
Ben Lindstrom1ee9ec32002-03-22 03:14:45 +0000603 fatal("chdir(\"/\"): %s", strerror(errno));
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000604
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000605 /* Drop our privileges */
Damien Miller6433df02006-09-07 10:36:43 +1000606 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid,
607 (u_int)privsep_pw->pw_gid);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000608#if 0
Darren Tuckerd5920482004-02-29 20:11:30 +1100609 /* XXX not ready, too heavy after chroot */
Damien Miller6433df02006-09-07 10:36:43 +1000610 do_setusercontext(privsep_pw);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000611#else
Damien Miller6433df02006-09-07 10:36:43 +1000612 gidset[0] = privsep_pw->pw_gid;
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000613 if (setgroups(1, gidset) < 0)
614 fatal("setgroups: %.100s", strerror(errno));
Damien Miller6433df02006-09-07 10:36:43 +1000615 permanently_set_uid(privsep_pw);
Ben Lindstromfbcc3f72002-06-25 23:24:18 +0000616#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000617}
618
Darren Tucker3e33cec2003-10-02 16:12:36 +1000619static int
620privsep_preauth(Authctxt *authctxt)
Ben Lindstrom943481c2002-03-22 03:43:46 +0000621{
Ben Lindstrom943481c2002-03-22 03:43:46 +0000622 int status;
623 pid_t pid;
624
625 /* Set up unprivileged child process to deal with network data */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000626 pmonitor = monitor_init();
Ben Lindstrom943481c2002-03-22 03:43:46 +0000627 /* Store a pointer to the kex for later rekeying */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000628 pmonitor->m_pkex = &xxx_kex;
Ben Lindstrom943481c2002-03-22 03:43:46 +0000629
630 pid = fork();
631 if (pid == -1) {
632 fatal("fork of unprivileged child failed");
633 } else if (pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000634 debug2("Network child is on pid %ld", (long)pid);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000635
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000636 close(pmonitor->m_recvfd);
Darren Tuckera8be9e22004-02-06 16:40:27 +1100637 pmonitor->m_pid = pid;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000638 monitor_child_preauth(authctxt, pmonitor);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000639 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000640
641 /* Sync memory */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000642 monitor_sync(pmonitor);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000643
644 /* Wait for the child's exit status */
Ben Lindstrom47fd8112002-04-02 20:48:19 +0000645 while (waitpid(pid, &status, 0) < 0)
646 if (errno != EINTR)
647 break;
Darren Tucker3e33cec2003-10-02 16:12:36 +1000648 return (1);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000649 } else {
650 /* child */
651
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000652 close(pmonitor->m_sendfd);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000653
654 /* Demote the child */
655 if (getuid() == 0 || geteuid() == 0)
656 privsep_preauth_child();
Ben Lindstromf90f58d2002-03-26 01:53:03 +0000657 setproctitle("%s", "[net]");
Ben Lindstrom943481c2002-03-22 03:43:46 +0000658 }
Darren Tucker3e33cec2003-10-02 16:12:36 +1000659 return (0);
Ben Lindstrom943481c2002-03-22 03:43:46 +0000660}
661
Ben Lindstrom08105192002-03-22 02:50:06 +0000662static void
Ben Lindstrom943481c2002-03-22 03:43:46 +0000663privsep_postauth(Authctxt *authctxt)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000664{
Tim Rice9dd30812002-07-07 13:43:36 -0700665#ifdef DISABLE_FD_PASSING
Tim Rice8eff3192002-06-25 15:35:15 -0700666 if (1) {
667#else
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000668 if (authctxt->pw->pw_uid == 0 || options.use_login) {
Tim Rice8eff3192002-06-25 15:35:15 -0700669#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000670 /* File descriptor passing is broken or root login */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000671 use_privsep = 0;
Darren Tucker45b01422005-10-03 18:20:00 +1000672 goto skip;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000673 }
Ben Lindstrom6328ab32002-03-22 02:54:23 +0000674
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000675 /* New socket pair */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000676 monitor_reinit(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000677
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000678 pmonitor->m_pid = fork();
679 if (pmonitor->m_pid == -1)
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000680 fatal("fork of unprivileged child failed");
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000681 else if (pmonitor->m_pid != 0) {
Ben Lindstromce0f6342002-06-11 16:42:49 +0000682 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000683 close(pmonitor->m_recvfd);
Darren Tuckereb578622004-08-12 23:08:14 +1000684 buffer_clear(&loginmsg);
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000685 monitor_child_postauth(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000686
687 /* NEVERREACHED */
688 exit(0);
689 }
690
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000691 close(pmonitor->m_sendfd);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000692
693 /* Demote the private keys to public keys. */
694 demote_sensitive_data();
695
696 /* Drop privileges */
697 do_setusercontext(authctxt->pw);
698
Darren Tucker45b01422005-10-03 18:20:00 +1000699 skip:
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000700 /* It is safe now to apply the key state */
Ben Lindstrom7339b2a2002-05-15 16:25:01 +0000701 monitor_apply_keystate(pmonitor);
Damien Miller9786e6e2005-07-26 21:54:56 +1000702
703 /*
704 * Tell the packet layer that authentication was successful, since
705 * this information is not part of the key state.
706 */
707 packet_set_authenticated();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000708}
709
Ben Lindstrombba81212001-06-25 05:01:22 +0000710static char *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100711list_hostkey_types(void)
712{
Damien Miller0e3b8722002-01-22 23:26:38 +1100713 Buffer b;
Damien Millerf58b58c2003-11-17 21:18:23 +1100714 const char *p;
715 char *ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100716 int i;
Damien Miller0e3b8722002-01-22 23:26:38 +1100717
718 buffer_init(&b);
Damien Miller9f0f5c62001-12-21 14:45:46 +1100719 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100720 Key *key = sensitive_data.host_keys[i];
721 if (key == NULL)
722 continue;
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000723 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100724 case KEY_RSA:
725 case KEY_DSA:
Damien Miller0e3b8722002-01-22 23:26:38 +1100726 if (buffer_len(&b) > 0)
727 buffer_append(&b, ",", 1);
728 p = key_ssh_name(key);
729 buffer_append(&b, p, strlen(p));
Damien Miller0bc1bd82000-11-13 22:57:25 +1100730 break;
731 }
732 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100733 buffer_append(&b, "\0", 1);
Damien Millerf58b58c2003-11-17 21:18:23 +1100734 ret = xstrdup(buffer_ptr(&b));
Damien Miller0e3b8722002-01-22 23:26:38 +1100735 buffer_free(&b);
Damien Millerf58b58c2003-11-17 21:18:23 +1100736 debug("list_hostkey_types: %s", ret);
737 return ret;
Damien Miller0bc1bd82000-11-13 22:57:25 +1100738}
739
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000740Key *
Damien Miller0bc1bd82000-11-13 22:57:25 +1100741get_hostkey_by_type(int type)
742{
743 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000744
Damien Miller9f0f5c62001-12-21 14:45:46 +1100745 for (i = 0; i < options.num_host_key_files; i++) {
Damien Miller0bc1bd82000-11-13 22:57:25 +1100746 Key *key = sensitive_data.host_keys[i];
747 if (key != NULL && key->type == type)
748 return key;
749 }
750 return NULL;
Damien Millerb38eff82000-04-01 11:09:21 +1000751}
752
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000753Key *
754get_hostkey_by_index(int ind)
755{
756 if (ind < 0 || ind >= options.num_host_key_files)
757 return (NULL);
758 return (sensitive_data.host_keys[ind]);
759}
760
761int
762get_hostkey_index(Key *key)
763{
764 int i;
Ben Lindstrom822b6342002-06-23 21:38:49 +0000765
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000766 for (i = 0; i < options.num_host_key_files; i++) {
767 if (key == sensitive_data.host_keys[i])
768 return (i);
769 }
770 return (-1);
771}
772
Damien Miller942da032000-08-18 13:59:06 +1000773/*
774 * returns 1 if connection should be dropped, 0 otherwise.
775 * dropping starts at connection #max_startups_begin with a probability
776 * of (max_startups_rate/100). the probability increases linearly until
777 * all connections are dropped for startups > max_startups
778 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000779static int
Damien Miller942da032000-08-18 13:59:06 +1000780drop_connection(int startups)
781{
Darren Tucker178fa662004-11-05 20:09:09 +1100782 int p, r;
Damien Miller942da032000-08-18 13:59:06 +1000783
784 if (startups < options.max_startups_begin)
785 return 0;
786 if (startups >= options.max_startups)
787 return 1;
788 if (options.max_startups_rate == 100)
789 return 1;
790
791 p = 100 - options.max_startups_rate;
792 p *= startups - options.max_startups_begin;
Darren Tucker178fa662004-11-05 20:09:09 +1100793 p /= options.max_startups - options.max_startups_begin;
Damien Miller942da032000-08-18 13:59:06 +1000794 p += options.max_startups_rate;
Darren Tucker178fa662004-11-05 20:09:09 +1100795 r = arc4random() % 100;
Damien Miller942da032000-08-18 13:59:06 +1000796
Darren Tucker3269b132004-11-05 20:20:59 +1100797 debug("drop_connection: p %d, r %d", p, r);
Damien Miller942da032000-08-18 13:59:06 +1000798 return (r < p) ? 1 : 0;
799}
800
Ben Lindstromade03f62001-12-06 18:22:17 +0000801static void
802usage(void)
803{
Damien Miller0c889cd2004-03-22 09:36:00 +1100804 fprintf(stderr, "%s, %s\n",
Damien Miller2aa6d3c2004-09-12 16:53:04 +1000805 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
Damien Millerb4087862004-03-22 09:35:21 +1100806 fprintf(stderr,
807"usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n"
808" [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n"
809 );
Ben Lindstromade03f62001-12-06 18:22:17 +0000810 exit(1);
811}
812
Darren Tucker645ab752004-06-25 13:33:20 +1000813static void
814send_rexec_state(int fd, Buffer *conf)
815{
816 Buffer m;
817
818 debug3("%s: entering fd = %d config len %d", __func__, fd,
819 buffer_len(conf));
820
821 /*
822 * Protocol from reexec master to child:
823 * string configuration
824 * u_int ephemeral_key_follows
825 * bignum e (only if ephemeral_key_follows == 1)
826 * bignum n "
827 * bignum d "
828 * bignum iqmp "
829 * bignum p "
830 * bignum q "
Darren Tuckerc6f82192005-09-27 22:46:32 +1000831 * string rngseed (only if OpenSSL is not self-seeded)
Darren Tucker645ab752004-06-25 13:33:20 +1000832 */
833 buffer_init(&m);
834 buffer_put_cstring(&m, buffer_ptr(conf));
835
Darren Tuckerfc959702004-07-17 16:12:08 +1000836 if (sensitive_data.server_key != NULL &&
Darren Tucker645ab752004-06-25 13:33:20 +1000837 sensitive_data.server_key->type == KEY_RSA1) {
838 buffer_put_int(&m, 1);
839 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
840 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
841 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
842 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
843 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
844 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
845 } else
846 buffer_put_int(&m, 0);
847
Darren Tuckerc6f82192005-09-27 22:46:32 +1000848#ifndef OPENSSL_PRNG_ONLY
849 rexec_send_rng_seed(&m);
850#endif
851
Darren Tucker645ab752004-06-25 13:33:20 +1000852 if (ssh_msg_send(fd, 0, &m) == -1)
853 fatal("%s: ssh_msg_send failed", __func__);
854
855 buffer_free(&m);
856
857 debug3("%s: done", __func__);
858}
859
860static void
861recv_rexec_state(int fd, Buffer *conf)
862{
863 Buffer m;
864 char *cp;
865 u_int len;
866
867 debug3("%s: entering fd = %d", __func__, fd);
868
869 buffer_init(&m);
870
871 if (ssh_msg_recv(fd, &m) == -1)
872 fatal("%s: ssh_msg_recv failed", __func__);
873 if (buffer_get_char(&m) != 0)
874 fatal("%s: rexec version mismatch", __func__);
875
876 cp = buffer_get_string(&m, &len);
877 if (conf != NULL)
878 buffer_append(conf, cp, len + 1);
879 xfree(cp);
880
881 if (buffer_get_int(&m)) {
882 if (sensitive_data.server_key != NULL)
883 key_free(sensitive_data.server_key);
884 sensitive_data.server_key = key_new_private(KEY_RSA1);
885 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
886 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
887 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
888 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
889 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
890 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
891 rsa_generate_additional_parameters(
892 sensitive_data.server_key->rsa);
893 }
Darren Tuckerc6f82192005-09-27 22:46:32 +1000894
895#ifndef OPENSSL_PRNG_ONLY
896 rexec_recv_rng_seed(&m);
897#endif
898
Darren Tucker645ab752004-06-25 13:33:20 +1000899 buffer_free(&m);
900
901 debug3("%s: done", __func__);
902}
903
Damien Millera1f68402006-08-19 00:31:39 +1000904/* Accept a connection from inetd */
905static void
906server_accept_inetd(int *sock_in, int *sock_out)
907{
908 int fd;
909
910 startup_pipe = -1;
911 if (rexeced_flag) {
912 close(REEXEC_CONFIG_PASS_FD);
913 *sock_in = *sock_out = dup(STDIN_FILENO);
914 if (!debug_flag) {
915 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
916 close(REEXEC_STARTUP_PIPE_FD);
917 }
918 } else {
919 *sock_in = dup(STDIN_FILENO);
920 *sock_out = dup(STDOUT_FILENO);
921 }
922 /*
923 * We intentionally do not close the descriptors 0, 1, and 2
924 * as our code for setting the descriptors won't work if
925 * ttyfd happens to be one of those.
926 */
927 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
928 dup2(fd, STDIN_FILENO);
929 dup2(fd, STDOUT_FILENO);
930 if (fd > STDOUT_FILENO)
931 close(fd);
932 }
933 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
934}
935
936/*
937 * Listen for TCP connections
938 */
939static void
940server_listen(void)
941{
942 int ret, listen_sock, on = 1;
943 struct addrinfo *ai;
944 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
945
946 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
947 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
948 continue;
949 if (num_listen_socks >= MAX_LISTEN_SOCKS)
950 fatal("Too many listen sockets. "
951 "Enlarge MAX_LISTEN_SOCKS");
952 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
953 ntop, sizeof(ntop), strport, sizeof(strport),
954 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
955 error("getnameinfo failed: %.100s",
Darren Tucker4abde772007-12-29 02:43:51 +1100956 ssh_gai_strerror(ret));
Damien Millera1f68402006-08-19 00:31:39 +1000957 continue;
958 }
959 /* Create socket for listening. */
960 listen_sock = socket(ai->ai_family, ai->ai_socktype,
961 ai->ai_protocol);
962 if (listen_sock < 0) {
963 /* kernel may not support ipv6 */
964 verbose("socket: %.100s", strerror(errno));
965 continue;
966 }
967 if (set_nonblock(listen_sock) == -1) {
968 close(listen_sock);
969 continue;
970 }
971 /*
972 * Set socket options.
973 * Allow local port reuse in TIME_WAIT.
974 */
975 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
976 &on, sizeof(on)) == -1)
977 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
978
Damien Miller49d2a282008-01-20 08:56:00 +1100979#ifdef IPV6_V6ONLY
980 /* Only communicate in IPv6 over AF_INET6 sockets. */
981 if (ai->ai_family == AF_INET6) {
982 if (setsockopt(listen_sock, IPPROTO_IPV6, IPV6_V6ONLY,
983 &on, sizeof(on)) == -1)
984 error("setsockopt IPV6_V6ONLY: %s",
985 strerror(errno));
986 }
987#endif
988
Damien Millera1f68402006-08-19 00:31:39 +1000989 debug("Bind to port %s on %s.", strport, ntop);
990
991 /* Bind the socket to the desired port. */
992 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
993 error("Bind to port %s on %s failed: %.200s.",
994 strport, ntop, strerror(errno));
995 close(listen_sock);
996 continue;
997 }
998 listen_socks[num_listen_socks] = listen_sock;
999 num_listen_socks++;
1000
1001 /* Start listening on the port. */
1002 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1003 fatal("listen on [%s]:%s: %.100s",
1004 ntop, strport, strerror(errno));
1005 logit("Server listening on %s port %s.", ntop, strport);
1006 }
1007 freeaddrinfo(options.listen_addrs);
1008
1009 if (!num_listen_socks)
1010 fatal("Cannot bind any address.");
1011}
1012
1013/*
1014 * The main TCP accept loop. Note that, for the non-debug case, returns
1015 * from this function are in a forked subprocess.
1016 */
1017static void
1018server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1019{
1020 fd_set *fdset;
1021 int i, j, ret, maxfd;
1022 int key_used = 0, startups = 0;
1023 int startup_p[2] = { -1 , -1 };
1024 struct sockaddr_storage from;
1025 socklen_t fromlen;
1026 pid_t pid;
1027
1028 /* setup fd set for accept */
1029 fdset = NULL;
1030 maxfd = 0;
1031 for (i = 0; i < num_listen_socks; i++)
1032 if (listen_socks[i] > maxfd)
1033 maxfd = listen_socks[i];
1034 /* pipes connected to unauthenticated childs */
1035 startup_pipes = xcalloc(options.max_startups, sizeof(int));
1036 for (i = 0; i < options.max_startups; i++)
1037 startup_pipes[i] = -1;
1038
1039 /*
1040 * Stay listening for connections until the system crashes or
1041 * the daemon is killed with a signal.
1042 */
1043 for (;;) {
1044 if (received_sighup)
1045 sighup_restart();
1046 if (fdset != NULL)
1047 xfree(fdset);
1048 fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS),
1049 sizeof(fd_mask));
1050
1051 for (i = 0; i < num_listen_socks; i++)
1052 FD_SET(listen_socks[i], fdset);
1053 for (i = 0; i < options.max_startups; i++)
1054 if (startup_pipes[i] != -1)
1055 FD_SET(startup_pipes[i], fdset);
1056
1057 /* Wait in select until there is a connection. */
1058 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1059 if (ret < 0 && errno != EINTR)
1060 error("select: %.100s", strerror(errno));
1061 if (received_sigterm) {
1062 logit("Received signal %d; terminating.",
1063 (int) received_sigterm);
1064 close_listen_socks();
1065 unlink(options.pid_file);
1066 exit(255);
1067 }
1068 if (key_used && key_do_regen) {
1069 generate_ephemeral_server_key();
1070 key_used = 0;
1071 key_do_regen = 0;
1072 }
1073 if (ret < 0)
1074 continue;
1075
1076 for (i = 0; i < options.max_startups; i++)
1077 if (startup_pipes[i] != -1 &&
1078 FD_ISSET(startup_pipes[i], fdset)) {
1079 /*
1080 * the read end of the pipe is ready
1081 * if the child has closed the pipe
1082 * after successful authentication
1083 * or if the child has died
1084 */
1085 close(startup_pipes[i]);
1086 startup_pipes[i] = -1;
1087 startups--;
1088 }
1089 for (i = 0; i < num_listen_socks; i++) {
1090 if (!FD_ISSET(listen_socks[i], fdset))
1091 continue;
1092 fromlen = sizeof(from);
1093 *newsock = accept(listen_socks[i],
1094 (struct sockaddr *)&from, &fromlen);
1095 if (*newsock < 0) {
1096 if (errno != EINTR && errno != EWOULDBLOCK)
1097 error("accept: %.100s", strerror(errno));
1098 continue;
1099 }
1100 if (unset_nonblock(*newsock) == -1) {
1101 close(*newsock);
1102 continue;
1103 }
1104 if (drop_connection(startups) == 1) {
1105 debug("drop connection #%d", startups);
1106 close(*newsock);
1107 continue;
1108 }
1109 if (pipe(startup_p) == -1) {
1110 close(*newsock);
1111 continue;
1112 }
1113
1114 if (rexec_flag && socketpair(AF_UNIX,
1115 SOCK_STREAM, 0, config_s) == -1) {
1116 error("reexec socketpair: %s",
1117 strerror(errno));
1118 close(*newsock);
1119 close(startup_p[0]);
1120 close(startup_p[1]);
1121 continue;
1122 }
1123
1124 for (j = 0; j < options.max_startups; j++)
1125 if (startup_pipes[j] == -1) {
1126 startup_pipes[j] = startup_p[0];
1127 if (maxfd < startup_p[0])
1128 maxfd = startup_p[0];
1129 startups++;
1130 break;
1131 }
1132
1133 /*
1134 * Got connection. Fork a child to handle it, unless
1135 * we are in debugging mode.
1136 */
1137 if (debug_flag) {
1138 /*
1139 * In debugging mode. Close the listening
1140 * socket, and start processing the
1141 * connection without forking.
1142 */
1143 debug("Server will not fork when running in debugging mode.");
1144 close_listen_socks();
1145 *sock_in = *newsock;
1146 *sock_out = *newsock;
1147 close(startup_p[0]);
1148 close(startup_p[1]);
1149 startup_pipe = -1;
1150 pid = getpid();
1151 if (rexec_flag) {
1152 send_rexec_state(config_s[0],
1153 &cfg);
1154 close(config_s[0]);
1155 }
1156 break;
1157 }
1158
1159 /*
1160 * Normal production daemon. Fork, and have
1161 * the child process the connection. The
1162 * parent continues listening.
1163 */
Damien Miller1b06dc32006-08-31 03:24:41 +10001164 platform_pre_fork();
Damien Millera1f68402006-08-19 00:31:39 +10001165 if ((pid = fork()) == 0) {
1166 /*
1167 * Child. Close the listening and
1168 * max_startup sockets. Start using
1169 * the accepted socket. Reinitialize
1170 * logging (since our pid has changed).
1171 * We break out of the loop to handle
1172 * the connection.
1173 */
Damien Miller1b06dc32006-08-31 03:24:41 +10001174 platform_post_fork_child();
Damien Millera1f68402006-08-19 00:31:39 +10001175 startup_pipe = startup_p[1];
1176 close_startup_pipes();
1177 close_listen_socks();
1178 *sock_in = *newsock;
1179 *sock_out = *newsock;
1180 log_init(__progname,
1181 options.log_level,
1182 options.log_facility,
1183 log_stderr);
1184 if (rexec_flag)
1185 close(config_s[0]);
1186 break;
1187 }
1188
1189 /* Parent. Stay in the loop. */
Damien Miller1b06dc32006-08-31 03:24:41 +10001190 platform_post_fork_parent(pid);
Damien Millera1f68402006-08-19 00:31:39 +10001191 if (pid < 0)
1192 error("fork: %.100s", strerror(errno));
1193 else
1194 debug("Forked child %ld.", (long)pid);
1195
1196 close(startup_p[1]);
1197
1198 if (rexec_flag) {
1199 send_rexec_state(config_s[0], &cfg);
1200 close(config_s[0]);
1201 close(config_s[1]);
1202 }
1203
1204 /*
1205 * Mark that the key has been used (it
1206 * was "given" to the child).
1207 */
1208 if ((options.protocol & SSH_PROTO_1) &&
1209 key_used == 0) {
1210 /* Schedule server key regeneration alarm. */
1211 signal(SIGALRM, key_regeneration_alarm);
1212 alarm(options.key_regeneration_time);
1213 key_used = 1;
1214 }
1215
1216 close(*newsock);
1217
1218 /*
1219 * Ensure that our random state differs
1220 * from that of the child
1221 */
1222 arc4random_stir();
1223 }
1224
1225 /* child process check (or debug mode) */
1226 if (num_listen_socks < 0)
1227 break;
1228 }
1229}
1230
1231
Damien Miller95def091999-11-25 00:26:21 +11001232/*
1233 * Main program for the daemon.
1234 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001235int
1236main(int ac, char **av)
1237{
Damien Miller95def091999-11-25 00:26:21 +11001238 extern char *optarg;
1239 extern int optind;
Damien Millera1f68402006-08-19 00:31:39 +10001240 int opt, i, on = 1;
Damien Miller386c6a22004-06-30 22:40:20 +10001241 int sock_in = -1, sock_out = -1, newsock = -1;
Damien Miller95def091999-11-25 00:26:21 +11001242 const char *remote_ip;
1243 int remote_port;
Damien Millerb9997192003-12-17 16:29:22 +11001244 char *line;
Damien Millera1f68402006-08-19 00:31:39 +10001245 int config_s[2] = { -1 , -1 };
Ben Lindstromd0fca422001-03-26 13:44:06 +00001246 Key *key;
Darren Tucker3e33cec2003-10-02 16:12:36 +10001247 Authctxt *authctxt;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001248
Kevin Steves0ea1d9d2002-04-25 18:17:04 +00001249#ifdef HAVE_SECUREWARE
1250 (void)set_auth_parameters(ac, av);
1251#endif
Damien Miller59d3d5b2003-08-22 09:34:41 +10001252 __progname = ssh_get_progname(av[0]);
Damien Millerf9b625c2000-07-09 22:42:32 +10001253 init_rng();
1254
Damien Millera8ed44b2003-01-10 09:53:12 +11001255 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
Damien Millerb8c656e2000-06-28 15:22:41 +10001256 saved_argc = ac;
Darren Tucker17c5d032004-06-25 14:22:23 +10001257 rexec_argc = ac;
Darren Tuckerd8093e42006-05-04 16:24:34 +10001258 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
Damien Millera8ed44b2003-01-10 09:53:12 +11001259 for (i = 0; i < ac; i++)
1260 saved_argv[i] = xstrdup(av[i]);
Damien Miller04cb5362003-05-15 21:29:10 +10001261 saved_argv[i] = NULL;
Damien Millera8ed44b2003-01-10 09:53:12 +11001262
1263#ifndef HAVE_SETPROCTITLE
1264 /* Prepare for later setproctitle emulation */
1265 compat_init_setproctitle(ac, av);
Damien Millerf2e3e9d2003-06-02 12:15:54 +10001266 av = saved_argv;
Damien Millera8ed44b2003-01-10 09:53:12 +11001267#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001268
Damien Millerbfba3542004-03-22 09:29:57 +11001269 if (geteuid() == 0 && setgroups(0, NULL) == -1)
1270 debug("setgroups(): %.200s", strerror(errno));
1271
Darren Tuckerce321d82005-10-03 18:11:24 +10001272 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1273 sanitise_stdfd();
1274
Damien Miller95def091999-11-25 00:26:21 +11001275 /* Initialize configuration options to their default values. */
1276 initialize_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001277
Damien Miller95def091999-11-25 00:26:21 +11001278 /* Parse command-line arguments. */
Darren Tucker645ab752004-06-25 13:33:20 +10001279 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) {
Damien Miller95def091999-11-25 00:26:21 +11001280 switch (opt) {
Damien Miller34132e52000-01-14 15:45:46 +11001281 case '4':
Darren Tucker0f383232005-01-20 10:57:56 +11001282 options.address_family = AF_INET;
Damien Miller34132e52000-01-14 15:45:46 +11001283 break;
1284 case '6':
Darren Tucker0f383232005-01-20 10:57:56 +11001285 options.address_family = AF_INET6;
Damien Miller34132e52000-01-14 15:45:46 +11001286 break;
Damien Miller95def091999-11-25 00:26:21 +11001287 case 'f':
1288 config_file_name = optarg;
1289 break;
1290 case 'd':
Darren Tuckere98dfa32003-07-19 19:54:31 +10001291 if (debug_flag == 0) {
Damien Millere4340be2000-09-16 13:29:08 +11001292 debug_flag = 1;
1293 options.log_level = SYSLOG_LEVEL_DEBUG1;
Darren Tuckere98dfa32003-07-19 19:54:31 +10001294 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
Damien Millere4340be2000-09-16 13:29:08 +11001295 options.log_level++;
Damien Miller95def091999-11-25 00:26:21 +11001296 break;
Ben Lindstromc72745a2000-12-02 19:03:54 +00001297 case 'D':
1298 no_daemon_flag = 1;
1299 break;
Ben Lindstrom9fce9f02001-04-11 23:10:09 +00001300 case 'e':
1301 log_stderr = 1;
1302 break;
Damien Miller95def091999-11-25 00:26:21 +11001303 case 'i':
1304 inetd_flag = 1;
1305 break;
Darren Tucker645ab752004-06-25 13:33:20 +10001306 case 'r':
1307 rexec_flag = 0;
1308 break;
1309 case 'R':
1310 rexeced_flag = 1;
1311 inetd_flag = 1;
1312 break;
Damien Miller95def091999-11-25 00:26:21 +11001313 case 'Q':
Ben Lindstromd5390202001-01-29 08:07:43 +00001314 /* ignored */
Damien Miller95def091999-11-25 00:26:21 +11001315 break;
1316 case 'q':
1317 options.log_level = SYSLOG_LEVEL_QUIET;
1318 break;
1319 case 'b':
Damien Millerf0b15df2006-03-26 13:59:20 +11001320 options.server_key_bits = (int)strtonum(optarg, 256,
1321 32768, NULL);
Damien Miller95def091999-11-25 00:26:21 +11001322 break;
1323 case 'p':
Damien Miller34132e52000-01-14 15:45:46 +11001324 options.ports_from_cmdline = 1;
Damien Millere4340be2000-09-16 13:29:08 +11001325 if (options.num_ports >= MAX_PORTS) {
1326 fprintf(stderr, "too many ports.\n");
1327 exit(1);
1328 }
Ben Lindstrom19066a12001-04-12 23:39:26 +00001329 options.ports[options.num_ports++] = a2port(optarg);
1330 if (options.ports[options.num_ports-1] == 0) {
1331 fprintf(stderr, "Bad port number.\n");
1332 exit(1);
1333 }
Damien Miller95def091999-11-25 00:26:21 +11001334 break;
1335 case 'g':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +00001336 if ((options.login_grace_time = convtime(optarg)) == -1) {
1337 fprintf(stderr, "Invalid login grace time.\n");
1338 exit(1);
1339 }
Damien Miller95def091999-11-25 00:26:21 +11001340 break;
1341 case 'k':
Ben Lindstrom1bda4c82001-06-05 19:59:08 +00001342 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
1343 fprintf(stderr, "Invalid key regeneration interval.\n");
1344 exit(1);
1345 }
Damien Miller95def091999-11-25 00:26:21 +11001346 break;
1347 case 'h':
Damien Miller0bc1bd82000-11-13 22:57:25 +11001348 if (options.num_host_key_files >= MAX_HOSTKEYS) {
1349 fprintf(stderr, "too many host keys.\n");
1350 exit(1);
1351 }
1352 options.host_key_files[options.num_host_key_files++] = optarg;
Damien Miller95def091999-11-25 00:26:21 +11001353 break;
Ben Lindstrom794325a2001-08-06 21:09:07 +00001354 case 't':
1355 test_flag = 1;
1356 break;
Damien Miller942da032000-08-18 13:59:06 +10001357 case 'u':
Damien Millerf0b15df2006-03-26 13:59:20 +11001358 utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL);
Ben Lindstrom41daec72002-07-23 21:15:13 +00001359 if (utmp_len > MAXHOSTNAMELEN) {
1360 fprintf(stderr, "Invalid utmp length.\n");
1361 exit(1);
1362 }
Damien Miller942da032000-08-18 13:59:06 +10001363 break;
Ben Lindstromade03f62001-12-06 18:22:17 +00001364 case 'o':
Damien Millerb9997192003-12-17 16:29:22 +11001365 line = xstrdup(optarg);
1366 if (process_server_config_line(&options, line,
Darren Tucker45150472006-07-12 22:34:17 +10001367 "command-line", 0, NULL, NULL, NULL, NULL) != 0)
Damien Miller9f0f5c62001-12-21 14:45:46 +11001368 exit(1);
Damien Millerb9997192003-12-17 16:29:22 +11001369 xfree(line);
Ben Lindstromade03f62001-12-06 18:22:17 +00001370 break;
Damien Miller95def091999-11-25 00:26:21 +11001371 case '?':
1372 default:
Ben Lindstromade03f62001-12-06 18:22:17 +00001373 usage();
1374 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001375 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001376 }
Darren Tucker645ab752004-06-25 13:33:20 +10001377 if (rexeced_flag || inetd_flag)
1378 rexec_flag = 0;
1379 if (rexec_flag && (av[0] == NULL || *av[0] != '/'))
1380 fatal("sshd re-exec requires execution with an absolute path");
1381 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001382 closefrom(REEXEC_MIN_FREE_FD);
1383 else
1384 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001385
Ben Lindstrom425fb022001-03-29 00:31:20 +00001386 SSLeay_add_all_algorithms();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001387
Damien Miller34132e52000-01-14 15:45:46 +11001388 /*
1389 * Force logging to stderr until we have loaded the private host
1390 * key (unless started from inetd)
1391 */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001392 log_init(__progname,
Damien Miller5aa5d782002-02-08 22:01:54 +11001393 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1394 SYSLOG_LEVEL_INFO : options.log_level,
1395 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1396 SYSLOG_FACILITY_AUTH : options.log_facility,
Ben Lindstromc2faa4a2002-11-09 15:50:03 +00001397 log_stderr || !inetd_flag);
Damien Miller34132e52000-01-14 15:45:46 +11001398
Darren Tucker86c093d2004-03-08 22:59:03 +11001399 /*
1400 * Unset KRB5CCNAME, otherwise the user's session may inherit it from
1401 * root's environment
Damien Miller94cf4c82005-07-17 17:04:47 +10001402 */
Darren Tucker9dc6c7d2005-02-02 18:30:33 +11001403 if (getenv("KRB5CCNAME") != NULL)
1404 unsetenv("KRB5CCNAME");
1405
Tim Rice81ed5182002-09-25 17:38:46 -07001406#ifdef _UNICOS
Darren Tucker12984962004-05-24 13:37:13 +10001407 /* Cray can define user privs drop all privs now!
Ben Lindstrom6db66ff2001-08-06 23:29:16 +00001408 * Not needed on PRIV_SU systems!
1409 */
1410 drop_cray_privs();
1411#endif
1412
Darren Tucker645ab752004-06-25 13:33:20 +10001413 sensitive_data.server_key = NULL;
1414 sensitive_data.ssh1_host_key = NULL;
1415 sensitive_data.have_ssh1_key = 0;
1416 sensitive_data.have_ssh2_key = 0;
1417
1418 /* Fetch our configuration */
1419 buffer_init(&cfg);
1420 if (rexeced_flag)
Damien Miller035a5b42004-06-26 08:16:31 +10001421 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
Darren Tucker645ab752004-06-25 13:33:20 +10001422 else
1423 load_server_config(config_file_name, &cfg);
1424
Darren Tucker45150472006-07-12 22:34:17 +10001425 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1426 &cfg, NULL, NULL, NULL);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001427
Darren Tuckerc6f82192005-09-27 22:46:32 +10001428 seed_rng();
1429
Damien Miller95def091999-11-25 00:26:21 +11001430 /* Fill in default values for those options not explicitly set. */
1431 fill_default_server_options(&options);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001432
Darren Tucker97b1bb52007-03-21 20:38:53 +11001433 /* challenge-response is implemented via keyboard interactive */
1434 if (options.challenge_response_authentication)
1435 options.kbd_interactive_authentication = 1;
1436
Darren Tucker0f383232005-01-20 10:57:56 +11001437 /* set default channel AF */
1438 channel_set_af(options.address_family);
1439
Damien Miller95def091999-11-25 00:26:21 +11001440 /* Check that there are no remaining arguments. */
1441 if (optind < ac) {
1442 fprintf(stderr, "Extra argument %s.\n", av[optind]);
1443 exit(1);
1444 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001445
Damien Miller2aa6d3c2004-09-12 16:53:04 +10001446 debug("sshd version %.100s", SSH_RELEASE);
Damien Miller2ccf6611999-11-15 15:25:10 +11001447
Darren Tuckerdf0e4382006-11-07 11:28:40 +11001448 /* Store privilege separation user for later use if required. */
1449 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
1450 if (use_privsep || options.kerberos_authentication)
1451 fatal("Privilege separation user %s does not exist",
1452 SSH_PRIVSEP_USER);
1453 } else {
1454 memset(privsep_pw->pw_passwd, 0, strlen(privsep_pw->pw_passwd));
1455 privsep_pw = pwcopy(privsep_pw);
1456 xfree(privsep_pw->pw_passwd);
1457 privsep_pw->pw_passwd = xstrdup("*");
1458 }
Damien Miller6433df02006-09-07 10:36:43 +10001459 endpwent();
1460
Damien Miller0bc1bd82000-11-13 22:57:25 +11001461 /* load private host keys */
Damien Miller07d86be2006-03-26 14:19:21 +11001462 sensitive_data.host_keys = xcalloc(options.num_host_key_files,
Ben Lindstroma962c2f2002-07-04 00:14:17 +00001463 sizeof(Key *));
Damien Miller9f0f5c62001-12-21 14:45:46 +11001464 for (i = 0; i < options.num_host_key_files; i++)
Ben Lindstrom46c16222000-12-22 01:43:59 +00001465 sensitive_data.host_keys[i] = NULL;
Damien Millereba71ba2000-04-29 23:57:08 +10001466
Damien Miller9f0f5c62001-12-21 14:45:46 +11001467 for (i = 0; i < options.num_host_key_files; i++) {
Ben Lindstromd0fca422001-03-26 13:44:06 +00001468 key = key_load_private(options.host_key_files[i], "", NULL);
1469 sensitive_data.host_keys[i] = key;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001470 if (key == NULL) {
Ben Lindstrom15f33862001-04-16 02:00:02 +00001471 error("Could not load host key: %s",
1472 options.host_key_files[i]);
Ben Lindstromd0fca422001-03-26 13:44:06 +00001473 sensitive_data.host_keys[i] = NULL;
Damien Miller0bc1bd82000-11-13 22:57:25 +11001474 continue;
1475 }
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +00001476 switch (key->type) {
Damien Miller0bc1bd82000-11-13 22:57:25 +11001477 case KEY_RSA1:
1478 sensitive_data.ssh1_host_key = key;
1479 sensitive_data.have_ssh1_key = 1;
1480 break;
1481 case KEY_RSA:
1482 case KEY_DSA:
1483 sensitive_data.have_ssh2_key = 1;
1484 break;
1485 }
Ben Lindstromd0fca422001-03-26 13:44:06 +00001486 debug("private host key: #%d type %d %s", i, key->type,
1487 key_type(key));
Damien Miller0bc1bd82000-11-13 22:57:25 +11001488 }
1489 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001490 logit("Disabling protocol version 1. Could not load host key");
Damien Millereba71ba2000-04-29 23:57:08 +10001491 options.protocol &= ~SSH_PROTO_1;
1492 }
Damien Miller0bc1bd82000-11-13 22:57:25 +11001493 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
Damien Miller996acd22003-04-09 20:59:48 +10001494 logit("Disabling protocol version 2. Could not load host key");
Damien Miller0bc1bd82000-11-13 22:57:25 +11001495 options.protocol &= ~SSH_PROTO_2;
Damien Millereba71ba2000-04-29 23:57:08 +10001496 }
Kevin Stevesadf74cd2001-02-05 14:22:50 +00001497 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
Damien Miller996acd22003-04-09 20:59:48 +10001498 logit("sshd: no hostkeys available -- exiting.");
Damien Miller95def091999-11-25 00:26:21 +11001499 exit(1);
1500 }
Damien Miller95def091999-11-25 00:26:21 +11001501
Damien Millereba71ba2000-04-29 23:57:08 +10001502 /* Check certain values for sanity. */
1503 if (options.protocol & SSH_PROTO_1) {
1504 if (options.server_key_bits < 512 ||
1505 options.server_key_bits > 32768) {
1506 fprintf(stderr, "Bad server key size.\n");
1507 exit(1);
1508 }
1509 /*
1510 * Check that server and host key lengths differ sufficiently. This
1511 * is necessary to make double encryption work with rsaref. Oh, I
1512 * hate software patents. I dont know if this can go? Niels
1513 */
1514 if (options.server_key_bits >
Ben Lindstrom822b6342002-06-23 21:38:49 +00001515 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1516 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1517 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1518 SSH_KEY_BITS_RESERVED) {
Damien Millereba71ba2000-04-29 23:57:08 +10001519 options.server_key_bits =
Ben Lindstrom822b6342002-06-23 21:38:49 +00001520 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1521 SSH_KEY_BITS_RESERVED;
Damien Millereba71ba2000-04-29 23:57:08 +10001522 debug("Forcing server key to %d bits to make it differ from host key.",
1523 options.server_key_bits);
1524 }
1525 }
1526
Ben Lindstroma26ea632002-06-06 20:46:25 +00001527 if (use_privsep) {
Ben Lindstroma26ea632002-06-06 20:46:25 +00001528 struct stat st;
1529
Ben Lindstroma26ea632002-06-06 20:46:25 +00001530 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1531 (S_ISDIR(st.st_mode) == 0))
1532 fatal("Missing privilege separation directory: %s",
1533 _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstrom59627352002-06-27 18:02:21 +00001534
1535#ifdef HAVE_CYGWIN
1536 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1537 (st.st_uid != getuid () ||
1538 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1539#else
Ben Lindstrom2dfacb32002-06-23 00:33:47 +00001540 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
Ben Lindstrom59627352002-06-27 18:02:21 +00001541#endif
Damien Miller180fc5b2003-02-24 11:50:18 +11001542 fatal("%s must be owned by root and not group or "
1543 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
Ben Lindstroma26ea632002-06-06 20:46:25 +00001544 }
1545
Ben Lindstrom794325a2001-08-06 21:09:07 +00001546 /* Configuration looks good, so exit if in test mode. */
1547 if (test_flag)
1548 exit(0);
1549
Damien Miller87aea252002-05-10 12:20:24 +10001550 /*
1551 * Clear out any supplemental groups we may have inherited. This
1552 * prevents inadvertent creation of files with bad modes (in the
Damien Millera8e06ce2003-11-21 23:48:55 +11001553 * portable version at least, it's certainly possible for PAM
1554 * to create a file, and we can't control the code in every
Damien Miller87aea252002-05-10 12:20:24 +10001555 * module which might be used).
1556 */
1557 if (setgroups(0, NULL) < 0)
1558 debug("setgroups() failed: %.200s", strerror(errno));
1559
Darren Tucker645ab752004-06-25 13:33:20 +10001560 if (rexec_flag) {
Damien Miller07d86be2006-03-26 14:19:21 +11001561 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
Darren Tucker645ab752004-06-25 13:33:20 +10001562 for (i = 0; i < rexec_argc; i++) {
1563 debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1564 rexec_argv[i] = saved_argv[i];
1565 }
1566 rexec_argv[rexec_argc] = "-R";
1567 rexec_argv[rexec_argc + 1] = NULL;
1568 }
1569
Damien Millereba71ba2000-04-29 23:57:08 +10001570 /* Initialize the log (it is reinitialized below in case we forked). */
Darren Tuckerea7c8122005-01-20 11:03:08 +11001571 if (debug_flag && (!inetd_flag || rexeced_flag))
Damien Miller95def091999-11-25 00:26:21 +11001572 log_stderr = 1;
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 Millereba71ba2000-04-29 23:57:08 +10001575 /*
1576 * If not in debugging mode, and not started from inetd, disconnect
1577 * from the controlling terminal, and fork. The original process
1578 * exits.
1579 */
Ben Lindstromc72745a2000-12-02 19:03:54 +00001580 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
Damien Miller95def091999-11-25 00:26:21 +11001581#ifdef TIOCNOTTY
1582 int fd;
1583#endif /* TIOCNOTTY */
1584 if (daemon(0, 0) < 0)
1585 fatal("daemon() failed: %.200s", strerror(errno));
1586
1587 /* Disconnect from the controlling tty. */
1588#ifdef TIOCNOTTY
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00001589 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
Damien Miller95def091999-11-25 00:26:21 +11001590 if (fd >= 0) {
1591 (void) ioctl(fd, TIOCNOTTY, NULL);
1592 close(fd);
1593 }
1594#endif /* TIOCNOTTY */
1595 }
1596 /* Reinitialize the log (because of the fork above). */
Kevin Stevesec84dc12000-12-13 17:45:15 +00001597 log_init(__progname, options.log_level, options.log_facility, log_stderr);
Damien Miller95def091999-11-25 00:26:21 +11001598
Damien Miller95def091999-11-25 00:26:21 +11001599 /* Initialize the random number generator. */
1600 arc4random_stir();
1601
1602 /* Chdir to the root directory so that the current disk can be
1603 unmounted if desired. */
1604 chdir("/");
Damien Miller9f0f5c62001-12-21 14:45:46 +11001605
Ben Lindstromde71cda2001-03-24 00:43:26 +00001606 /* ignore SIGPIPE */
1607 signal(SIGPIPE, SIG_IGN);
Damien Miller95def091999-11-25 00:26:21 +11001608
Damien Millera1f68402006-08-19 00:31:39 +10001609 /* Get a connection, either from inetd or a listening TCP socket */
Damien Miller95def091999-11-25 00:26:21 +11001610 if (inetd_flag) {
Damien Millera1f68402006-08-19 00:31:39 +10001611 server_accept_inetd(&sock_in, &sock_out);
Damien Miller95def091999-11-25 00:26:21 +11001612 } else {
Damien Millera1f68402006-08-19 00:31:39 +10001613 server_listen();
Damien Miller34132e52000-01-14 15:45:46 +11001614
Ben Lindstrom98097862001-06-25 05:10:20 +00001615 if (options.protocol & SSH_PROTO_1)
1616 generate_ephemeral_server_key();
1617
Ben Lindstrom98097862001-06-25 05:10:20 +00001618 signal(SIGHUP, sighup_handler);
Damien Millera1f68402006-08-19 00:31:39 +10001619 signal(SIGCHLD, main_sigchld_handler);
Ben Lindstrom98097862001-06-25 05:10:20 +00001620 signal(SIGTERM, sigterm_handler);
1621 signal(SIGQUIT, sigterm_handler);
1622
Damien Millera1f68402006-08-19 00:31:39 +10001623 /*
1624 * Write out the pid file after the sigterm handler
1625 * is setup and the listen sockets are bound
1626 */
Damien Miller95def091999-11-25 00:26:21 +11001627 if (!debug_flag) {
Damien Millera1f68402006-08-19 00:31:39 +10001628 FILE *f = fopen(options.pid_file, "w");
1629
Darren Tuckere5327042003-07-03 13:40:44 +10001630 if (f == NULL) {
1631 error("Couldn't create pid file \"%s\": %s",
1632 options.pid_file, strerror(errno));
1633 } else {
Ben Lindstromce0f6342002-06-11 16:42:49 +00001634 fprintf(f, "%ld\n", (long) getpid());
Damien Miller95def091999-11-25 00:26:21 +11001635 fclose(f);
1636 }
1637 }
Damien Miller95def091999-11-25 00:26:21 +11001638
Damien Millera1f68402006-08-19 00:31:39 +10001639 /* Accept a connection and return in a forked child */
1640 server_accept_loop(&sock_in, &sock_out,
1641 &newsock, config_s);
Damien Miller95def091999-11-25 00:26:21 +11001642 }
1643
1644 /* This is the child processing a new connection. */
Damien Miller57aae982004-03-08 23:11:25 +11001645 setproctitle("%s", "[accepted]");
Damien Miller95def091999-11-25 00:26:21 +11001646
Darren Tucker6832b832004-08-12 22:36:51 +10001647 /*
1648 * Create a new session and process group since the 4.4BSD
1649 * setlogin() affects the entire process group. We don't
1650 * want the child to be able to affect the parent.
1651 */
1652#if !defined(SSHD_ACQUIRES_CTTY)
1653 /*
1654 * If setsid is called, on some platforms sshd will later acquire a
1655 * controlling terminal which will result in "could not set
1656 * controlling tty" errors.
1657 */
1658 if (!debug_flag && !inetd_flag && setsid() < 0)
1659 error("setsid: %.100s", strerror(errno));
1660#endif
1661
Darren Tucker645ab752004-06-25 13:33:20 +10001662 if (rexec_flag) {
1663 int fd;
1664
Damien Miller035a5b42004-06-26 08:16:31 +10001665 debug("rexec start in %d out %d newsock %d pipe %d sock %d",
1666 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001667 dup2(newsock, STDIN_FILENO);
1668 dup2(STDIN_FILENO, STDOUT_FILENO);
1669 if (startup_pipe == -1)
Damien Miller035a5b42004-06-26 08:16:31 +10001670 close(REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001671 else
Damien Miller035a5b42004-06-26 08:16:31 +10001672 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001673
Damien Miller035a5b42004-06-26 08:16:31 +10001674 dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
Darren Tucker645ab752004-06-25 13:33:20 +10001675 close(config_s[1]);
Darren Tuckerd8835932004-08-12 22:42:29 +10001676 if (startup_pipe != -1)
1677 close(startup_pipe);
Damien Miller035a5b42004-06-26 08:16:31 +10001678
Darren Tucker645ab752004-06-25 13:33:20 +10001679 execv(rexec_argv[0], rexec_argv);
1680
1681 /* Reexec has failed, fall back and continue */
1682 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
Damien Miller035a5b42004-06-26 08:16:31 +10001683 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
Darren Tucker645ab752004-06-25 13:33:20 +10001684 log_init(__progname, options.log_level,
1685 options.log_facility, log_stderr);
1686
1687 /* Clean up fds */
Damien Miller035a5b42004-06-26 08:16:31 +10001688 startup_pipe = REEXEC_STARTUP_PIPE_FD;
Darren Tucker645ab752004-06-25 13:33:20 +10001689 close(config_s[1]);
Damien Miller035a5b42004-06-26 08:16:31 +10001690 close(REEXEC_CONFIG_PASS_FD);
1691 newsock = sock_out = sock_in = dup(STDIN_FILENO);
Darren Tucker645ab752004-06-25 13:33:20 +10001692 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1693 dup2(fd, STDIN_FILENO);
1694 dup2(fd, STDOUT_FILENO);
1695 if (fd > STDERR_FILENO)
1696 close(fd);
1697 }
Damien Miller035a5b42004-06-26 08:16:31 +10001698 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
1699 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
Darren Tucker645ab752004-06-25 13:33:20 +10001700 }
1701
Damien Miller5428f641999-11-25 11:54:57 +11001702 /*
1703 * Disable the key regeneration alarm. We will not regenerate the
1704 * key since we are no longer in a position to give it to anyone. We
1705 * will not restart on SIGHUP since it no longer makes sense.
1706 */
Damien Miller95def091999-11-25 00:26:21 +11001707 alarm(0);
1708 signal(SIGALRM, SIG_DFL);
1709 signal(SIGHUP, SIG_DFL);
1710 signal(SIGTERM, SIG_DFL);
1711 signal(SIGQUIT, SIG_DFL);
1712 signal(SIGCHLD, SIG_DFL);
Damien Miller4e0f5e12000-08-29 11:05:50 +11001713 signal(SIGINT, SIG_DFL);
Damien Miller95def091999-11-25 00:26:21 +11001714
Damien Miller5428f641999-11-25 11:54:57 +11001715 /*
1716 * Register our connection. This turns encryption off because we do
1717 * not have a key.
1718 */
Damien Miller95def091999-11-25 00:26:21 +11001719 packet_set_connection(sock_in, sock_out);
Damien Miller9786e6e2005-07-26 21:54:56 +10001720 packet_set_server();
Damien Miller95def091999-11-25 00:26:21 +11001721
Damien Miller4f1d6b22005-05-26 11:59:32 +10001722 /* Set SO_KEEPALIVE if requested. */
1723 if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
1724 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
1725 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1726
Damien Miller677257f2005-06-17 12:55:03 +10001727 if ((remote_port = get_remote_port()) < 0) {
1728 debug("get_remote_port failed");
1729 cleanup_exit(255);
1730 }
Damien Miller4d3fd542005-11-05 15:13:24 +11001731
1732 /*
1733 * We use get_canonical_hostname with usedns = 0 instead of
1734 * get_remote_ipaddr here so IP options will be checked.
1735 */
Damien Millereb13e552006-06-13 13:03:53 +10001736 (void) get_canonical_hostname(0);
1737 /*
1738 * The rest of the code depends on the fact that
1739 * get_remote_ipaddr() caches the remote ip, even if
1740 * the socket goes away.
1741 */
1742 remote_ip = get_remote_ipaddr();
Damien Miller95def091999-11-25 00:26:21 +11001743
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001744#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11001745 audit_connection_from(remote_ip, remote_port);
1746#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001747#ifdef LIBWRAP
Damien Miller6a4a4b92001-11-12 11:07:11 +11001748 /* Check whether logins are denied from this host. */
Darren Tucker586b0b92004-06-25 13:34:31 +10001749 if (packet_connection_is_on_socket()) {
Damien Miller95def091999-11-25 00:26:21 +11001750 struct request_info req;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001751
Ben Lindstromce89dac2001-09-12 16:58:04 +00001752 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
Damien Miller95def091999-11-25 00:26:21 +11001753 fromhost(&req);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001754
Damien Miller95def091999-11-25 00:26:21 +11001755 if (!hosts_access(&req)) {
Damien Miller6a4a4b92001-11-12 11:07:11 +11001756 debug("Connection refused by tcp wrapper");
Ben Lindstrom7de696e2001-03-29 00:45:12 +00001757 refuse(&req);
Damien Miller6a4a4b92001-11-12 11:07:11 +11001758 /* NOTREACHED */
1759 fatal("libwrap refuse returns");
Damien Miller95def091999-11-25 00:26:21 +11001760 }
Damien Miller95def091999-11-25 00:26:21 +11001761 }
Damien Miller34132e52000-01-14 15:45:46 +11001762#endif /* LIBWRAP */
Damien Miller6a4a4b92001-11-12 11:07:11 +11001763
Damien Miller95def091999-11-25 00:26:21 +11001764 /* Log the connection. */
1765 verbose("Connection from %.500s port %d", remote_ip, remote_port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001766
Damien Miller5428f641999-11-25 11:54:57 +11001767 /*
Damien Miller788f2122005-11-05 15:14:59 +11001768 * We don't want to listen forever unless the other side
Damien Miller5428f641999-11-25 11:54:57 +11001769 * successfully authenticates itself. So we set up an alarm which is
1770 * cleared after successful authentication. A limit of zero
Damien Miller788f2122005-11-05 15:14:59 +11001771 * indicates no limit. Note that we don't set the alarm in debugging
Damien Miller5428f641999-11-25 11:54:57 +11001772 * mode; it is just annoying to have the server exit just when you
1773 * are about to discover the bug.
1774 */
Ben Lindstrom5ade9ab2003-08-25 01:16:21 +00001775 signal(SIGALRM, grace_alarm_handler);
Damien Miller95def091999-11-25 00:26:21 +11001776 if (!debug_flag)
1777 alarm(options.login_grace_time);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001778
Damien Millerb38eff82000-04-01 11:09:21 +10001779 sshd_exchange_identification(sock_in, sock_out);
Darren Tuckerec960f22003-08-13 20:37:05 +10001780
Darren Tucker58911162008-01-01 20:33:09 +11001781 /* In inetd mode, generate ephemeral key only for proto 1 connections */
1782 if (!compat20 && inetd_flag && sensitive_data.server_key == NULL)
1783 generate_ephemeral_server_key();
1784
Damien Miller95def091999-11-25 00:26:21 +11001785 packet_set_nonblocking();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001786
Darren Tucker3e33cec2003-10-02 16:12:36 +10001787 /* allocate authentication context */
Damien Miller07d86be2006-03-26 14:19:21 +11001788 authctxt = xcalloc(1, sizeof(*authctxt));
Darren Tucker3e33cec2003-10-02 16:12:36 +10001789
Darren Tuckerf3bb4342005-03-31 21:39:25 +10001790 authctxt->loginmsg = &loginmsg;
1791
Darren Tucker3e33cec2003-10-02 16:12:36 +10001792 /* XXX global for cleanup, access from other modules */
1793 the_authctxt = authctxt;
1794
Darren Tucker5c14c732005-01-24 21:55:49 +11001795 /* prepare buffer to collect messages to display to user after login */
1796 buffer_init(&loginmsg);
1797
Ben Lindstrom943481c2002-03-22 03:43:46 +00001798 if (use_privsep)
Darren Tucker3e33cec2003-10-02 16:12:36 +10001799 if (privsep_preauth(authctxt) == 1)
Ben Lindstrom943481c2002-03-22 03:43:46 +00001800 goto authenticated;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001801
Damien Miller396691a2000-01-20 22:44:08 +11001802 /* perform the key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001803 /* authenticate user and start session */
Damien Millerefb4afe2000-04-12 18:45:05 +10001804 if (compat20) {
1805 do_ssh2_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001806 do_authentication2(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001807 } else {
1808 do_ssh1_kex();
Darren Tucker3e33cec2003-10-02 16:12:36 +10001809 do_authentication(authctxt);
Damien Millerefb4afe2000-04-12 18:45:05 +10001810 }
Ben Lindstrom943481c2002-03-22 03:43:46 +00001811 /*
1812 * If we use privilege separation, the unprivileged child transfers
1813 * the current keystate and exits
1814 */
1815 if (use_privsep) {
Ben Lindstrom7339b2a2002-05-15 16:25:01 +00001816 mm_send_keystate(pmonitor);
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001817 exit(0);
Ben Lindstrom943481c2002-03-22 03:43:46 +00001818 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001819
1820 authenticated:
Damien Miller7bff1a92005-12-24 14:59:12 +11001821 /*
1822 * Cancel the alarm we set to limit the time taken for
1823 * authentication.
1824 */
1825 alarm(0);
1826 signal(SIGALRM, SIG_DFL);
Damien Miller3f8123c2006-08-19 00:32:46 +10001827 authctxt->authenticated = 1;
Damien Miller7bff1a92005-12-24 14:59:12 +11001828 if (startup_pipe != -1) {
1829 close(startup_pipe);
1830 startup_pipe = -1;
1831 }
1832
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11001833#ifdef SSH_AUDIT_EVENTS
1834 audit_event(SSH_AUTH_SUCCESS);
Darren Tucker269a1ea2005-02-03 00:20:53 +11001835#endif
1836
Ben Lindstrom6328ab32002-03-22 02:54:23 +00001837 /*
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001838 * In privilege separation, we fork another child and prepare
1839 * file descriptor passing.
1840 */
1841 if (use_privsep) {
Ben Lindstrom943481c2002-03-22 03:43:46 +00001842 privsep_postauth(authctxt);
1843 /* the monitor process [priv] will not return */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001844 if (!compat20)
1845 destroy_sensitive_data();
1846 }
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001847
Darren Tucker3e33cec2003-10-02 16:12:36 +10001848 /* Start session. */
Ben Lindstrom73ab9ba2002-03-22 01:27:35 +00001849 do_authenticated(authctxt);
1850
Damien Miller3a5b0232002-03-13 13:19:42 +11001851 /* The connection has been terminated. */
1852 verbose("Closing connection to %.100s", remote_ip);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001853
Damien Millerbeb4ba51999-12-28 15:09:35 +11001854#ifdef USE_PAM
Damien Miller4e448a32003-05-14 15:11:48 +10001855 if (options.use_pam)
1856 finish_pam();
Damien Millerbeb4ba51999-12-28 15:09:35 +11001857#endif /* USE_PAM */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001858
Darren Tucker2b59a6d2005-03-06 22:38:51 +11001859#ifdef SSH_AUDIT_EVENTS
1860 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE));
1861#endif
1862
Damien Miller95def091999-11-25 00:26:21 +11001863 packet_close();
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001864
1865 if (use_privsep)
1866 mm_terminate();
1867
Damien Miller95def091999-11-25 00:26:21 +11001868 exit(0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001869}
1870
Damien Miller95def091999-11-25 00:26:21 +11001871/*
Ben Lindstromabcb1452002-03-22 01:10:21 +00001872 * Decrypt session_key_int using our private server key and private host key
1873 * (key with larger modulus first).
1874 */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00001875int
Ben Lindstromabcb1452002-03-22 01:10:21 +00001876ssh1_session_key(BIGNUM *session_key_int)
1877{
1878 int rsafail = 0;
1879
Damien Millerf0b15df2006-03-26 13:59:20 +11001880 if (BN_cmp(sensitive_data.server_key->rsa->n,
1881 sensitive_data.ssh1_host_key->rsa->n) > 0) {
Ben Lindstromabcb1452002-03-22 01:10:21 +00001882 /* Server key has bigger modulus. */
1883 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
Damien Millerf0b15df2006-03-26 13:59:20 +11001884 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1885 SSH_KEY_BITS_RESERVED) {
1886 fatal("do_connection: %s: "
1887 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
Ben Lindstromabcb1452002-03-22 01:10:21 +00001888 get_remote_ipaddr(),
1889 BN_num_bits(sensitive_data.server_key->rsa->n),
1890 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1891 SSH_KEY_BITS_RESERVED);
1892 }
1893 if (rsa_private_decrypt(session_key_int, session_key_int,
1894 sensitive_data.server_key->rsa) <= 0)
1895 rsafail++;
1896 if (rsa_private_decrypt(session_key_int, session_key_int,
1897 sensitive_data.ssh1_host_key->rsa) <= 0)
1898 rsafail++;
1899 } else {
1900 /* Host key has bigger modulus (or they are equal). */
1901 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
Damien Millerf0b15df2006-03-26 13:59:20 +11001902 BN_num_bits(sensitive_data.server_key->rsa->n) +
1903 SSH_KEY_BITS_RESERVED) {
1904 fatal("do_connection: %s: "
1905 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
Ben Lindstromabcb1452002-03-22 01:10:21 +00001906 get_remote_ipaddr(),
1907 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1908 BN_num_bits(sensitive_data.server_key->rsa->n),
1909 SSH_KEY_BITS_RESERVED);
1910 }
1911 if (rsa_private_decrypt(session_key_int, session_key_int,
1912 sensitive_data.ssh1_host_key->rsa) < 0)
1913 rsafail++;
1914 if (rsa_private_decrypt(session_key_int, session_key_int,
1915 sensitive_data.server_key->rsa) < 0)
1916 rsafail++;
1917 }
1918 return (rsafail);
1919}
1920/*
Damien Miller396691a2000-01-20 22:44:08 +11001921 * SSH1 key exchange
Damien Miller95def091999-11-25 00:26:21 +11001922 */
Ben Lindstrombba81212001-06-25 05:01:22 +00001923static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00001924do_ssh1_kex(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001925{
Damien Miller95def091999-11-25 00:26:21 +11001926 int i, len;
Damien Miller7650bc62001-01-30 09:27:26 +11001927 int rsafail = 0;
Damien Miller95def091999-11-25 00:26:21 +11001928 BIGNUM *session_key_int;
Ben Lindstrom46c16222000-12-22 01:43:59 +00001929 u_char session_key[SSH_SESSION_KEY_LENGTH];
1930 u_char cookie[8];
1931 u_int cipher_type, auth_mask, protocol_flags;
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001932 u_int32_t rnd = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001933
Damien Miller5428f641999-11-25 11:54:57 +11001934 /*
1935 * Generate check bytes that the client must send back in the user
1936 * packet in order for it to be accepted; this is used to defy ip
1937 * spoofing attacks. Note that this only works against somebody
1938 * doing IP spoofing from a remote machine; any machine on the local
1939 * network can still see outgoing packets and catch the random
1940 * cookie. This only affects rhosts authentication, and this is one
1941 * of the reasons why it is inherently insecure.
1942 */
Damien Miller95def091999-11-25 00:26:21 +11001943 for (i = 0; i < 8; i++) {
1944 if (i % 4 == 0)
Ben Lindstrom5a9d0ea2002-07-04 00:12:53 +00001945 rnd = arc4random();
1946 cookie[i] = rnd & 0xff;
1947 rnd >>= 8;
Damien Miller95def091999-11-25 00:26:21 +11001948 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001949
Damien Miller5428f641999-11-25 11:54:57 +11001950 /*
1951 * Send our public key. We include in the packet 64 bits of random
1952 * data that must be matched in the reply in order to prevent IP
1953 * spoofing.
1954 */
Damien Miller95def091999-11-25 00:26:21 +11001955 packet_start(SSH_SMSG_PUBLIC_KEY);
1956 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11001957 packet_put_char(cookie[i]);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001958
Damien Miller95def091999-11-25 00:26:21 +11001959 /* Store our public server RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001960 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1961 packet_put_bignum(sensitive_data.server_key->rsa->e);
1962 packet_put_bignum(sensitive_data.server_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001963
Damien Miller95def091999-11-25 00:26:21 +11001964 /* Store our public host RSA key. */
Damien Miller0bc1bd82000-11-13 22:57:25 +11001965 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1966 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1967 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001968
Damien Miller95def091999-11-25 00:26:21 +11001969 /* Put protocol flags. */
1970 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001971
Damien Miller95def091999-11-25 00:26:21 +11001972 /* Declare which ciphers we support. */
Damien Miller874d77b2000-10-14 16:23:11 +11001973 packet_put_int(cipher_mask_ssh1(0));
Damien Miller95def091999-11-25 00:26:21 +11001974
1975 /* Declare supported authentication types. */
1976 auth_mask = 0;
Damien Miller95def091999-11-25 00:26:21 +11001977 if (options.rhosts_rsa_authentication)
1978 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1979 if (options.rsa_authentication)
1980 auth_mask |= 1 << SSH_AUTH_RSA;
Ben Lindstrom551ea372001-06-05 18:56:16 +00001981 if (options.challenge_response_authentication == 1)
Damien Miller95def091999-11-25 00:26:21 +11001982 auth_mask |= 1 << SSH_AUTH_TIS;
Damien Miller95def091999-11-25 00:26:21 +11001983 if (options.password_authentication)
1984 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1985 packet_put_int(auth_mask);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001986
Damien Miller95def091999-11-25 00:26:21 +11001987 /* Send the packet and wait for it to be sent. */
1988 packet_send();
1989 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001990
Damien Miller0bc1bd82000-11-13 22:57:25 +11001991 debug("Sent %d bit server key and %d bit host key.",
1992 BN_num_bits(sensitive_data.server_key->rsa->n),
1993 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001994
Damien Miller95def091999-11-25 00:26:21 +11001995 /* Read clients reply (cipher type and session key). */
Damien Millerdff50992002-01-22 23:16:32 +11001996 packet_read_expect(SSH_CMSG_SESSION_KEY);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001997
Damien Miller50945fa1999-12-09 10:31:37 +11001998 /* Get cipher type and check whether we accept this. */
Damien Miller95def091999-11-25 00:26:21 +11001999 cipher_type = packet_get_char();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002000
Damien Miller874d77b2000-10-14 16:23:11 +11002001 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
Damien Miller50945fa1999-12-09 10:31:37 +11002002 packet_disconnect("Warning: client selects unsupported cipher.");
2003
Damien Miller95def091999-11-25 00:26:21 +11002004 /* Get check bytes from the packet. These must match those we
2005 sent earlier with the public key packet. */
2006 for (i = 0; i < 8; i++)
Damien Miller396691a2000-01-20 22:44:08 +11002007 if (cookie[i] != packet_get_char())
Damien Miller95def091999-11-25 00:26:21 +11002008 packet_disconnect("IP Spoofing check bytes do not match.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002009
Damien Miller95def091999-11-25 00:26:21 +11002010 debug("Encryption type: %.200s", cipher_name(cipher_type));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002011
Damien Miller95def091999-11-25 00:26:21 +11002012 /* Get the encrypted integer. */
Damien Millerda755162002-01-22 23:09:22 +11002013 if ((session_key_int = BN_new()) == NULL)
2014 fatal("do_ssh1_kex: BN_new failed");
Damien Millerd432ccf2002-01-22 23:14:44 +11002015 packet_get_bignum(session_key_int);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002016
Damien Miller95def091999-11-25 00:26:21 +11002017 protocol_flags = packet_get_int();
2018 packet_set_protocol_flags(protocol_flags);
Damien Miller48b03fc2002-01-22 23:11:40 +11002019 packet_check_eom();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002020
Ben Lindstromabcb1452002-03-22 01:10:21 +00002021 /* Decrypt session_key_int using host/server keys */
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002022 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
2023
Damien Miller5428f641999-11-25 11:54:57 +11002024 /*
2025 * Extract session key from the decrypted integer. The key is in the
2026 * least significant 256 bits of the integer; the first byte of the
2027 * key is in the highest bits.
2028 */
Damien Miller7650bc62001-01-30 09:27:26 +11002029 if (!rsafail) {
Darren Tucker0bc85572006-11-07 23:14:41 +11002030 (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8);
Damien Miller7650bc62001-01-30 09:27:26 +11002031 len = BN_num_bytes(session_key_int);
Damien Millereccb9de2005-06-17 12:59:34 +10002032 if (len < 0 || (u_int)len > sizeof(session_key)) {
Darren Tucker0bc85572006-11-07 23:14:41 +11002033 error("do_ssh1_kex: bad session key len from %s: "
Ben Lindstrom31ca54a2001-02-09 02:11:24 +00002034 "session_key_int %d > sizeof(session_key) %lu",
2035 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
Damien Miller7650bc62001-01-30 09:27:26 +11002036 rsafail++;
2037 } else {
2038 memset(session_key, 0, sizeof(session_key));
2039 BN_bn2bin(session_key_int,
2040 session_key + sizeof(session_key) - len);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002041
Darren Tuckere14e0052004-05-13 16:30:44 +10002042 derive_ssh1_session_id(
Darren Tuckerfc959702004-07-17 16:12:08 +10002043 sensitive_data.ssh1_host_key->rsa->n,
Darren Tuckere14e0052004-05-13 16:30:44 +10002044 sensitive_data.server_key->rsa->n,
2045 cookie, session_id);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002046 /*
2047 * Xor the first 16 bytes of the session key with the
2048 * session id.
2049 */
2050 for (i = 0; i < 16; i++)
2051 session_key[i] ^= session_id[i];
Damien Miller7650bc62001-01-30 09:27:26 +11002052 }
2053 }
2054 if (rsafail) {
Ben Lindstromeb648a72001-03-05 06:00:29 +00002055 int bytes = BN_num_bytes(session_key_int);
Ben Lindstrom13c5d3b2002-02-26 18:00:48 +00002056 u_char *buf = xmalloc(bytes);
Ben Lindstromeb648a72001-03-05 06:00:29 +00002057 MD5_CTX md;
2058
Damien Miller996acd22003-04-09 20:59:48 +10002059 logit("do_connection: generating a fake encryption key");
Ben Lindstromeb648a72001-03-05 06:00:29 +00002060 BN_bn2bin(session_key_int, buf);
2061 MD5_Init(&md);
2062 MD5_Update(&md, buf, bytes);
2063 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
2064 MD5_Final(session_key, &md);
2065 MD5_Init(&md);
2066 MD5_Update(&md, session_key, 16);
2067 MD5_Update(&md, buf, bytes);
2068 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
2069 MD5_Final(session_key + 16, &md);
2070 memset(buf, 0, bytes);
2071 xfree(buf);
Ben Lindstrom941ac822001-03-05 06:25:23 +00002072 for (i = 0; i < 16; i++)
2073 session_id[i] = session_key[i] ^ session_key[i + 16];
Damien Miller7650bc62001-01-30 09:27:26 +11002074 }
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002075 /* Destroy the private and public keys. No longer. */
Damien Miller3a5b0232002-03-13 13:19:42 +11002076 destroy_sensitive_data();
Ben Lindstromeb648a72001-03-05 06:00:29 +00002077
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002078 if (use_privsep)
2079 mm_ssh1_session_id(session_id);
2080
Damien Miller396691a2000-01-20 22:44:08 +11002081 /* Destroy the decrypted integer. It is no longer needed. */
2082 BN_clear_free(session_key_int);
2083
Damien Miller95def091999-11-25 00:26:21 +11002084 /* Set the session key. From this on all communications will be encrypted. */
2085 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002086
Damien Miller95def091999-11-25 00:26:21 +11002087 /* Destroy our copy of the session key. It is no longer needed. */
2088 memset(session_key, 0, sizeof(session_key));
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002089
Damien Miller95def091999-11-25 00:26:21 +11002090 debug("Received session key; encryption turned on.");
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002091
Ben Lindstromf666fec2002-06-06 19:51:58 +00002092 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
Damien Miller95def091999-11-25 00:26:21 +11002093 packet_start(SSH_SMSG_SUCCESS);
2094 packet_send();
2095 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002096}
Damien Millerefb4afe2000-04-12 18:45:05 +10002097
2098/*
2099 * SSH2 key exchange: diffie-hellman-group1-sha1
2100 */
Ben Lindstrombba81212001-06-25 05:01:22 +00002101static void
Ben Lindstrom46c16222000-12-22 01:43:59 +00002102do_ssh2_kex(void)
Damien Millerefb4afe2000-04-12 18:45:05 +10002103{
Damien Millerefb4afe2000-04-12 18:45:05 +10002104 Kex *kex;
Damien Millerefb4afe2000-04-12 18:45:05 +10002105
Damien Miller78928792000-04-12 20:17:38 +10002106 if (options.ciphers != NULL) {
Damien Miller4af51302000-04-16 11:18:38 +10002107 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
Damien Miller78928792000-04-12 20:17:38 +10002108 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
2109 }
Damien Millera0ff4662001-03-30 10:49:35 +10002110 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
2111 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
2112 myproposal[PROPOSAL_ENC_ALGS_STOC] =
2113 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
2114
Ben Lindstrom06b33aa2001-02-15 03:01:59 +00002115 if (options.macs != NULL) {
2116 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2117 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2118 }
Damien Miller9786e6e2005-07-26 21:54:56 +10002119 if (options.compression == COMP_NONE) {
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002120 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2121 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
Damien Miller9786e6e2005-07-26 21:54:56 +10002122 } else if (options.compression == COMP_DELAYED) {
2123 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2124 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
Ben Lindstrom23e0f662002-06-21 01:09:47 +00002125 }
Damien Millerf0b15df2006-03-26 13:59:20 +11002126
Damien Miller0bc1bd82000-11-13 22:57:25 +11002127 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
2128
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002129 /* start key exchange */
Ben Lindstrom238abf62001-04-04 17:52:53 +00002130 kex = kex_setup(myproposal);
Damien Miller8e7fb332003-02-24 12:03:03 +11002131 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
Damien Millerf675fc42004-06-15 10:30:09 +10002132 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
Damien Miller8e7fb332003-02-24 12:03:03 +11002133 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
Damien Millera63128d2006-03-15 12:08:28 +11002134 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002135 kex->server = 1;
2136 kex->client_version_string=client_version_string;
2137 kex->server_version_string=server_version_string;
2138 kex->load_host_key=&get_hostkey_by_type;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +00002139 kex->host_key_index=&get_hostkey_index;
Damien Millerefb4afe2000-04-12 18:45:05 +10002140
Ben Lindstrom8ac91062001-04-04 17:57:54 +00002141 xxx_kex = kex;
2142
Ben Lindstrombe2cc432001-04-04 23:46:07 +00002143 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
Damien Miller874d77b2000-10-14 16:23:11 +11002144
Ben Lindstrom2d90e002001-04-04 02:00:54 +00002145 session_id2 = kex->session_id;
2146 session_id2_len = kex->session_id_len;
2147
Damien Miller874d77b2000-10-14 16:23:11 +11002148#ifdef DEBUG_KEXDH
2149 /* send 1st encrypted/maced/compressed message */
2150 packet_start(SSH2_MSG_IGNORE);
2151 packet_put_cstring("markus");
2152 packet_send();
2153 packet_write_wait();
2154#endif
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +00002155 debug("KEX done");
Damien Millerefb4afe2000-04-12 18:45:05 +10002156}
Darren Tucker3e33cec2003-10-02 16:12:36 +10002157
2158/* server specific fatal cleanup */
2159void
2160cleanup_exit(int i)
2161{
2162 if (the_authctxt)
2163 do_cleanup(the_authctxt);
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002164#ifdef SSH_AUDIT_EVENTS
Darren Tucker269a1ea2005-02-03 00:20:53 +11002165 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
2166 if (!use_privsep || mm_is_monitor())
Darren Tucker2e0cf0d2005-02-08 21:52:47 +11002167 audit_event(SSH_CONNECTION_ABANDON);
Darren Tucker269a1ea2005-02-03 00:20:53 +11002168#endif
Darren Tucker3e33cec2003-10-02 16:12:36 +10002169 _exit(i);
2170}