Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 4 | * All rights reserved |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 5 | * This program is the ssh daemon. It listens for connections from clients, |
| 6 | * and performs authentication, executes use commands or shell, and forwards |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 7 | * information to/from the application to the user client over an encrypted |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 8 | * connection. This can also handle forwarding of X11, TCP/IP, and |
| 9 | * authentication agent connections. |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 10 | * |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 11 | * As far as I am concerned, the code I have written for this software |
| 12 | * can be used freely for any purpose. Any derived versions of this |
| 13 | * software must be clearly marked as such, and if the derived work is |
| 14 | * incompatible with the protocol description in the RFC file, it must be |
| 15 | * called by a name other than "ssh" or "Secure Shell". |
| 16 | * |
| 17 | * SSH2 implementation: |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 18 | * Privilege Separation: |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 19 | * |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 20 | * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. |
| 21 | * Copyright (c) 2002 Niels Provos. All rights reserved. |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 22 | * |
| 23 | * Redistribution and use in source and binary forms, with or without |
| 24 | * modification, are permitted provided that the following conditions |
| 25 | * are met: |
| 26 | * 1. Redistributions of source code must retain the above copyright |
| 27 | * notice, this list of conditions and the following disclaimer. |
| 28 | * 2. Redistributions in binary form must reproduce the above copyright |
| 29 | * notice, this list of conditions and the following disclaimer in the |
| 30 | * documentation and/or other materials provided with the distribution. |
| 31 | * |
| 32 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 33 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 34 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 35 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 36 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 37 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 38 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 39 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 40 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 41 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 42 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 43 | |
| 44 | #include "includes.h" |
Ben Lindstrom | c743134 | 2002-03-22 03:11:49 +0000 | [diff] [blame^] | 45 | RCSID("$OpenBSD: sshd.c,v 1.235 2002/03/20 19:12:25 stevesk Exp $"); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 46 | |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 47 | #include <openssl/dh.h> |
| 48 | #include <openssl/bn.h> |
Damien Miller | 6a47f30 | 2002-02-13 13:55:06 +1100 | [diff] [blame] | 49 | #include <openssl/md5.h> |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 50 | #include <openssl/rand.h> |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 51 | |
| 52 | #include "ssh.h" |
| 53 | #include "ssh1.h" |
| 54 | #include "ssh2.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 55 | #include "xmalloc.h" |
| 56 | #include "rsa.h" |
Ben Lindstrom | d95c09c | 2001-02-18 19:13:33 +0000 | [diff] [blame] | 57 | #include "sshpty.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 58 | #include "packet.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 59 | #include "mpaux.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 60 | #include "log.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 61 | #include "servconf.h" |
| 62 | #include "uidswap.h" |
| 63 | #include "compat.h" |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 64 | #include "buffer.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 65 | #include "cipher.h" |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 66 | #include "kex.h" |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 67 | #include "key.h" |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 68 | #include "dh.h" |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 69 | #include "myproposal.h" |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 70 | #include "authfile.h" |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 71 | #include "pathnames.h" |
| 72 | #include "atomicio.h" |
| 73 | #include "canohost.h" |
| 74 | #include "auth.h" |
| 75 | #include "misc.h" |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 76 | #include "dispatch.h" |
Ben Lindstrom | 1bae404 | 2001-10-03 17:46:39 +0000 | [diff] [blame] | 77 | #include "channels.h" |
Ben Lindstrom | 73ab9ba | 2002-03-22 01:27:35 +0000 | [diff] [blame] | 78 | #include "session.h" |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 79 | #include "monitor_mm.h" |
| 80 | #include "monitor.h" |
| 81 | #include "monitor_wrap.h" |
| 82 | #include "monitor_fdpass.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 83 | |
| 84 | #ifdef LIBWRAP |
| 85 | #include <tcpd.h> |
| 86 | #include <syslog.h> |
| 87 | int allow_severity = LOG_INFO; |
| 88 | int deny_severity = LOG_WARNING; |
| 89 | #endif /* LIBWRAP */ |
| 90 | |
| 91 | #ifndef O_NOCTTY |
| 92 | #define O_NOCTTY 0 |
| 93 | #endif |
| 94 | |
Ben Lindstrom | 49a79c0 | 2000-11-17 03:47:20 +0000 | [diff] [blame] | 95 | #ifdef HAVE___PROGNAME |
| 96 | extern char *__progname; |
| 97 | #else |
| 98 | char *__progname; |
| 99 | #endif |
| 100 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 101 | /* Server configuration options. */ |
| 102 | ServerOptions options; |
| 103 | |
| 104 | /* Name of the server configuration file. */ |
Ben Lindstrom | 226cfa0 | 2001-01-22 05:34:40 +0000 | [diff] [blame] | 105 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 106 | |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 107 | /* |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 108 | * Flag indicating whether IPv4 or IPv6. This can be set on the command line. |
| 109 | * Default value is AF_UNSPEC means both IPv4 and IPv6. |
| 110 | */ |
Damien Miller | 7d80e34 | 2000-01-19 14:36:49 +1100 | [diff] [blame] | 111 | #ifdef IPV4_DEFAULT |
| 112 | int IPv4or6 = AF_INET; |
| 113 | #else |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 114 | int IPv4or6 = AF_UNSPEC; |
Damien Miller | 7d80e34 | 2000-01-19 14:36:49 +1100 | [diff] [blame] | 115 | #endif |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 116 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 117 | /* |
| 118 | * Debug mode flag. This can be set on the command line. If debug |
| 119 | * mode is enabled, extra debugging output will be sent to the system |
| 120 | * log, the daemon will not go to background, and will exit after processing |
| 121 | * the first connection. |
| 122 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 123 | int debug_flag = 0; |
| 124 | |
Ben Lindstrom | 794325a | 2001-08-06 21:09:07 +0000 | [diff] [blame] | 125 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
| 126 | int test_flag = 0; |
| 127 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 128 | /* Flag indicating that the daemon is being started from inetd. */ |
| 129 | int inetd_flag = 0; |
| 130 | |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 131 | /* Flag indicating that sshd should not detach and become a daemon. */ |
| 132 | int no_daemon_flag = 0; |
| 133 | |
Damien Miller | 5ce662a | 1999-11-11 17:57:39 +1100 | [diff] [blame] | 134 | /* debug goes to stderr unless inetd_flag is set */ |
| 135 | int log_stderr = 0; |
| 136 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 137 | /* Saved arguments to main(). */ |
| 138 | char **saved_argv; |
Damien Miller | b8c656e | 2000-06-28 15:22:41 +1000 | [diff] [blame] | 139 | int saved_argc; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 140 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 141 | /* |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 142 | * The sockets that the server is listening; this is used in the SIGHUP |
| 143 | * signal handler. |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 144 | */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 145 | #define MAX_LISTEN_SOCKS 16 |
| 146 | int listen_socks[MAX_LISTEN_SOCKS]; |
| 147 | int num_listen_socks = 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 148 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 149 | /* |
| 150 | * the client's version string, passed by sshd2 in compat mode. if != NULL, |
| 151 | * sshd will skip the version-number exchange |
| 152 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 153 | char *client_version_string = NULL; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 154 | char *server_version_string = NULL; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 155 | |
Ben Lindstrom | 8ac9106 | 2001-04-04 17:57:54 +0000 | [diff] [blame] | 156 | /* for rekeying XXX fixme */ |
| 157 | Kex *xxx_kex; |
| 158 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 159 | /* |
| 160 | * Any really sensitive data in the application is contained in this |
| 161 | * structure. The idea is that this structure could be locked into memory so |
| 162 | * that the pages do not get written into swap. However, there are some |
| 163 | * problems. The private key contains BIGNUMs, and we do not (in principle) |
| 164 | * have access to the internals of them, and locking just the structure is |
| 165 | * not very useful. Currently, memory locking is not implemented. |
| 166 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 167 | struct { |
Ben Lindstrom | ca42d5f | 2001-03-09 18:25:32 +0000 | [diff] [blame] | 168 | Key *server_key; /* ephemeral server key */ |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 169 | Key *ssh1_host_key; /* ssh1 host key */ |
| 170 | Key **host_keys; /* all private host keys */ |
| 171 | int have_ssh1_key; |
| 172 | int have_ssh2_key; |
Ben Lindstrom | eb648a7 | 2001-03-05 06:00:29 +0000 | [diff] [blame] | 173 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 174 | } sensitive_data; |
| 175 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 176 | /* |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 177 | * Flag indicating whether the RSA server key needs to be regenerated. |
| 178 | * Is set in the SIGALRM handler and cleared when the key is regenerated. |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 179 | */ |
Ben Lindstrom | 5e71c54 | 2001-12-06 16:48:14 +0000 | [diff] [blame] | 180 | static volatile sig_atomic_t key_do_regen = 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 181 | |
Ben Lindstrom | ec46e0b | 2001-06-09 01:27:31 +0000 | [diff] [blame] | 182 | /* This is set to true when a signal is received. */ |
Ben Lindstrom | 5e71c54 | 2001-12-06 16:48:14 +0000 | [diff] [blame] | 183 | static volatile sig_atomic_t received_sighup = 0; |
| 184 | static volatile sig_atomic_t received_sigterm = 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 185 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 186 | /* session identifier, used by RSA-auth */ |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 187 | u_char session_id[16]; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 188 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 189 | /* same for ssh2 */ |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 190 | u_char *session_id2 = NULL; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 191 | int session_id2_len = 0; |
| 192 | |
Damien Miller | 942da03 | 2000-08-18 13:59:06 +1000 | [diff] [blame] | 193 | /* record remote hostname or ip */ |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 194 | u_int utmp_len = MAXHOSTNAMELEN; |
Damien Miller | 942da03 | 2000-08-18 13:59:06 +1000 | [diff] [blame] | 195 | |
Ben Lindstrom | d84df98 | 2001-12-06 16:35:40 +0000 | [diff] [blame] | 196 | /* options.max_startup sized array of fd ints */ |
| 197 | int *startup_pipes = NULL; |
| 198 | int startup_pipe; /* in child */ |
| 199 | |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 200 | /* variables used for privilege separation */ |
| 201 | extern struct monitor *monitor; |
| 202 | extern int use_privsep; |
| 203 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 204 | /* Prototypes for various functions defined later in this file. */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 205 | void destroy_sensitive_data(void); |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 206 | void demote_sensitive_data(void); |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 207 | |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 208 | static void do_ssh1_kex(void); |
| 209 | static void do_ssh2_kex(void); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 210 | |
Damien Miller | 98c7ad6 | 2000-03-09 21:27:49 +1100 | [diff] [blame] | 211 | /* |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 212 | * Close all listening sockets |
| 213 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 214 | static void |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 215 | close_listen_socks(void) |
| 216 | { |
| 217 | int i; |
| 218 | for (i = 0; i < num_listen_socks; i++) |
| 219 | close(listen_socks[i]); |
| 220 | num_listen_socks = -1; |
| 221 | } |
| 222 | |
Ben Lindstrom | d84df98 | 2001-12-06 16:35:40 +0000 | [diff] [blame] | 223 | static void |
| 224 | close_startup_pipes(void) |
| 225 | { |
| 226 | int i; |
| 227 | if (startup_pipes) |
| 228 | for (i = 0; i < options.max_startups; i++) |
| 229 | if (startup_pipes[i] != -1) |
| 230 | close(startup_pipes[i]); |
| 231 | } |
| 232 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 233 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 234 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; |
| 235 | * the effect is to reread the configuration file (and to regenerate |
| 236 | * the server key). |
| 237 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 238 | static void |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 239 | sighup_handler(int sig) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 240 | { |
Ben Lindstrom | 0795848 | 2001-12-06 16:19:01 +0000 | [diff] [blame] | 241 | int save_errno = errno; |
| 242 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 243 | received_sighup = 1; |
| 244 | signal(SIGHUP, sighup_handler); |
Ben Lindstrom | 0795848 | 2001-12-06 16:19:01 +0000 | [diff] [blame] | 245 | errno = save_errno; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 246 | } |
| 247 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 248 | /* |
| 249 | * Called from the main program after receiving SIGHUP. |
| 250 | * Restarts the server. |
| 251 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 252 | static void |
Ben Lindstrom | 31ca54a | 2001-02-09 02:11:24 +0000 | [diff] [blame] | 253 | sighup_restart(void) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 254 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 255 | log("Received SIGHUP; restarting."); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 256 | close_listen_socks(); |
Ben Lindstrom | d84df98 | 2001-12-06 16:35:40 +0000 | [diff] [blame] | 257 | close_startup_pipes(); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 258 | execv(saved_argv[0], saved_argv); |
Kevin Steves | ec84dc1 | 2000-12-13 17:45:15 +0000 | [diff] [blame] | 259 | log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 260 | exit(1); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 261 | } |
| 262 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 263 | /* |
| 264 | * Generic signal handler for terminating signals in the master daemon. |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 265 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 266 | static void |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 267 | sigterm_handler(int sig) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 268 | { |
Ben Lindstrom | ec46e0b | 2001-06-09 01:27:31 +0000 | [diff] [blame] | 269 | received_sigterm = sig; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 270 | } |
| 271 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 272 | /* |
| 273 | * SIGCHLD handler. This is called whenever a child dies. This will then |
Ben Lindstrom | ec46e0b | 2001-06-09 01:27:31 +0000 | [diff] [blame] | 274 | * reap any zombies left by exited children. |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 275 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 276 | static void |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 277 | main_sigchld_handler(int sig) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 278 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 279 | int save_errno = errno; |
| 280 | int status; |
Damien Miller | 431f66b | 1999-11-21 18:31:57 +1100 | [diff] [blame] | 281 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 282 | while (waitpid(-1, &status, WNOHANG) > 0) |
| 283 | ; |
Damien Miller | 431f66b | 1999-11-21 18:31:57 +1100 | [diff] [blame] | 284 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 285 | signal(SIGCHLD, main_sigchld_handler); |
| 286 | errno = save_errno; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 287 | } |
| 288 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 289 | /* |
| 290 | * Signal handler for the alarm after the login grace period has expired. |
| 291 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 292 | static void |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 293 | grace_alarm_handler(int sig) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 294 | { |
Ben Lindstrom | ec46e0b | 2001-06-09 01:27:31 +0000 | [diff] [blame] | 295 | /* XXX no idea how fix this signal handler */ |
| 296 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 297 | /* Close the connection. */ |
| 298 | packet_close(); |
| 299 | |
| 300 | /* Log error and exit. */ |
| 301 | fatal("Timeout before authentication for %s.", get_remote_ipaddr()); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 302 | } |
| 303 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 304 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 305 | * Signal handler for the key regeneration alarm. Note that this |
| 306 | * alarm only occurs in the daemon waiting for connections, and it does not |
| 307 | * do anything with the private key or random state before forking. |
| 308 | * Thus there should be no concurrency control/asynchronous execution |
| 309 | * problems. |
| 310 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 311 | static void |
Ben Lindstrom | ca42d5f | 2001-03-09 18:25:32 +0000 | [diff] [blame] | 312 | generate_ephemeral_server_key(void) |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 313 | { |
Ben Lindstrom | eb648a7 | 2001-03-05 06:00:29 +0000 | [diff] [blame] | 314 | u_int32_t rand = 0; |
| 315 | int i; |
| 316 | |
Ben Lindstrom | a370005 | 2001-04-05 23:26:32 +0000 | [diff] [blame] | 317 | verbose("Generating %s%d bit RSA key.", |
Damien Miller | ff75ac4 | 2001-03-30 10:50:32 +1000 | [diff] [blame] | 318 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 319 | if (sensitive_data.server_key != NULL) |
| 320 | key_free(sensitive_data.server_key); |
Ben Lindstrom | a370005 | 2001-04-05 23:26:32 +0000 | [diff] [blame] | 321 | sensitive_data.server_key = key_generate(KEY_RSA1, |
Damien Miller | ff75ac4 | 2001-03-30 10:50:32 +1000 | [diff] [blame] | 322 | options.server_key_bits); |
| 323 | verbose("RSA key generation complete."); |
Ben Lindstrom | eb648a7 | 2001-03-05 06:00:29 +0000 | [diff] [blame] | 324 | |
| 325 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { |
| 326 | if (i % 4 == 0) |
| 327 | rand = arc4random(); |
| 328 | sensitive_data.ssh1_cookie[i] = rand & 0xff; |
| 329 | rand >>= 8; |
| 330 | } |
| 331 | arc4random_stir(); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 332 | } |
Ben Lindstrom | 2f959b4 | 2001-01-11 06:20:23 +0000 | [diff] [blame] | 333 | |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 334 | static void |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 335 | key_regeneration_alarm(int sig) |
| 336 | { |
| 337 | int save_errno = errno; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 338 | signal(SIGALRM, SIG_DFL); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 339 | errno = save_errno; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 340 | key_do_regen = 1; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 341 | } |
| 342 | |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 343 | static void |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 344 | sshd_exchange_identification(int sock_in, int sock_out) |
| 345 | { |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 346 | int i, mismatch; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 347 | int remote_major, remote_minor; |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 348 | int major, minor; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 349 | char *s; |
| 350 | char buf[256]; /* Must not be larger than remote_version. */ |
| 351 | char remote_version[256]; /* Must be at least as big as buf. */ |
| 352 | |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 353 | if ((options.protocol & SSH_PROTO_1) && |
| 354 | (options.protocol & SSH_PROTO_2)) { |
| 355 | major = PROTOCOL_MAJOR_1; |
| 356 | minor = 99; |
| 357 | } else if (options.protocol & SSH_PROTO_2) { |
| 358 | major = PROTOCOL_MAJOR_2; |
| 359 | minor = PROTOCOL_MINOR_2; |
| 360 | } else { |
| 361 | major = PROTOCOL_MAJOR_1; |
| 362 | minor = PROTOCOL_MINOR_1; |
| 363 | } |
| 364 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 365 | server_version_string = xstrdup(buf); |
| 366 | |
| 367 | if (client_version_string == NULL) { |
| 368 | /* Send our protocol version identification. */ |
| 369 | if (atomicio(write, sock_out, server_version_string, strlen(server_version_string)) |
| 370 | != strlen(server_version_string)) { |
Damien Miller | e4a0ff4 | 2001-11-12 11:06:54 +1100 | [diff] [blame] | 371 | log("Could not write ident string to %s", get_remote_ipaddr()); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 372 | fatal_cleanup(); |
| 373 | } |
| 374 | |
Ben Lindstrom | 5393f93 | 2001-02-15 03:17:13 +0000 | [diff] [blame] | 375 | /* Read other side's version identification. */ |
Ben Lindstrom | a370005 | 2001-04-05 23:26:32 +0000 | [diff] [blame] | 376 | memset(buf, 0, sizeof(buf)); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 377 | for (i = 0; i < sizeof(buf) - 1; i++) { |
Damien Miller | bf7f466 | 2000-06-23 10:16:38 +1000 | [diff] [blame] | 378 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { |
Damien Miller | e4a0ff4 | 2001-11-12 11:06:54 +1100 | [diff] [blame] | 379 | log("Did not receive identification string from %s", |
Ben Lindstrom | a9a29e1 | 2001-02-20 01:20:47 +0000 | [diff] [blame] | 380 | get_remote_ipaddr()); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 381 | fatal_cleanup(); |
| 382 | } |
| 383 | if (buf[i] == '\r') { |
Ben Lindstrom | 69d8c07 | 2001-03-22 22:45:33 +0000 | [diff] [blame] | 384 | buf[i] = 0; |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 385 | /* Kludge for F-Secure Macintosh < 1.0.2 */ |
| 386 | if (i == 12 && |
| 387 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) |
| 388 | break; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 389 | continue; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 390 | } |
| 391 | if (buf[i] == '\n') { |
Ben Lindstrom | 69d8c07 | 2001-03-22 22:45:33 +0000 | [diff] [blame] | 392 | buf[i] = 0; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 393 | break; |
| 394 | } |
| 395 | } |
| 396 | buf[sizeof(buf) - 1] = 0; |
| 397 | client_version_string = xstrdup(buf); |
| 398 | } |
| 399 | |
| 400 | /* |
| 401 | * Check that the versions match. In future this might accept |
| 402 | * several versions and set appropriate flags to handle them. |
| 403 | */ |
| 404 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", |
| 405 | &remote_major, &remote_minor, remote_version) != 3) { |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 406 | s = "Protocol mismatch.\n"; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 407 | (void) atomicio(write, sock_out, s, strlen(s)); |
| 408 | close(sock_in); |
| 409 | close(sock_out); |
| 410 | log("Bad protocol version identification '%.100s' from %s", |
| 411 | client_version_string, get_remote_ipaddr()); |
| 412 | fatal_cleanup(); |
| 413 | } |
| 414 | debug("Client protocol version %d.%d; client software version %.100s", |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 415 | remote_major, remote_minor, remote_version); |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 416 | |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 417 | compat_datafellows(remote_version); |
| 418 | |
Damien Miller | 27dbe6f | 2001-03-19 22:36:20 +1100 | [diff] [blame] | 419 | if (datafellows & SSH_BUG_SCANNER) { |
| 420 | log("scanned from %s with %s. Don't panic.", |
| 421 | get_remote_ipaddr(), client_version_string); |
| 422 | fatal_cleanup(); |
| 423 | } |
| 424 | |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 425 | mismatch = 0; |
Ben Lindstrom | 1c37c6a | 2001-12-06 18:00:18 +0000 | [diff] [blame] | 426 | switch (remote_major) { |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 427 | case 1: |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 428 | if (remote_minor == 99) { |
| 429 | if (options.protocol & SSH_PROTO_2) |
| 430 | enable_compat20(); |
| 431 | else |
| 432 | mismatch = 1; |
| 433 | break; |
| 434 | } |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 435 | if (!(options.protocol & SSH_PROTO_1)) { |
| 436 | mismatch = 1; |
| 437 | break; |
| 438 | } |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 439 | if (remote_minor < 3) { |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 440 | packet_disconnect("Your ssh version is too old and " |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 441 | "is no longer supported. Please install a newer version."); |
| 442 | } else if (remote_minor == 3) { |
| 443 | /* note that this disables agent-forwarding */ |
| 444 | enable_compat13(); |
| 445 | } |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 446 | break; |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 447 | case 2: |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 448 | if (options.protocol & SSH_PROTO_2) { |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 449 | enable_compat20(); |
| 450 | break; |
| 451 | } |
| 452 | /* FALLTHROUGH */ |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 453 | default: |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 454 | mismatch = 1; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 455 | break; |
| 456 | } |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 457 | chop(server_version_string); |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 458 | debug("Local version string %.200s", server_version_string); |
| 459 | |
| 460 | if (mismatch) { |
| 461 | s = "Protocol major versions differ.\n"; |
| 462 | (void) atomicio(write, sock_out, s, strlen(s)); |
| 463 | close(sock_in); |
| 464 | close(sock_out); |
| 465 | log("Protocol major versions differ for %s: %.200s vs. %.200s", |
| 466 | get_remote_ipaddr(), |
| 467 | server_version_string, client_version_string); |
| 468 | fatal_cleanup(); |
| 469 | } |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 470 | } |
| 471 | |
| 472 | |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 473 | /* Destroy the host and server keys. They will no longer be needed. */ |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 474 | void |
| 475 | destroy_sensitive_data(void) |
| 476 | { |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 477 | int i; |
| 478 | |
| 479 | if (sensitive_data.server_key) { |
| 480 | key_free(sensitive_data.server_key); |
| 481 | sensitive_data.server_key = NULL; |
| 482 | } |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 483 | for (i = 0; i < options.num_host_key_files; i++) { |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 484 | if (sensitive_data.host_keys[i]) { |
| 485 | key_free(sensitive_data.host_keys[i]); |
| 486 | sensitive_data.host_keys[i] = NULL; |
| 487 | } |
| 488 | } |
| 489 | sensitive_data.ssh1_host_key = NULL; |
Ben Lindstrom | eb648a7 | 2001-03-05 06:00:29 +0000 | [diff] [blame] | 490 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 491 | } |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 492 | |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 493 | /* Demote private to public keys for network child */ |
| 494 | void |
| 495 | demote_sensitive_data(void) |
| 496 | { |
| 497 | Key *tmp; |
| 498 | int i; |
| 499 | |
| 500 | if (sensitive_data.server_key) { |
| 501 | tmp = key_demote(sensitive_data.server_key); |
| 502 | key_free(sensitive_data.server_key); |
| 503 | sensitive_data.server_key = tmp; |
| 504 | } |
| 505 | |
| 506 | for (i = 0; i < options.num_host_key_files; i++) { |
| 507 | if (sensitive_data.host_keys[i]) { |
| 508 | tmp = key_demote(sensitive_data.host_keys[i]); |
| 509 | key_free(sensitive_data.host_keys[i]); |
| 510 | sensitive_data.host_keys[i] = tmp; |
| 511 | if (tmp->type == KEY_RSA1) |
| 512 | sensitive_data.ssh1_host_key = tmp; |
| 513 | } |
| 514 | } |
| 515 | |
| 516 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ |
| 517 | } |
| 518 | |
Ben Lindstrom | 0810519 | 2002-03-22 02:50:06 +0000 | [diff] [blame] | 519 | static void |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 520 | privsep_preauth_child(void) |
| 521 | { |
| 522 | u_int32_t rand[256]; |
| 523 | int i; |
Ben Lindstrom | c743134 | 2002-03-22 03:11:49 +0000 | [diff] [blame^] | 524 | struct passwd *pw; |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 525 | |
| 526 | /* Enable challenge-response authentication for privilege separation */ |
| 527 | privsep_challenge_enable(); |
| 528 | |
| 529 | for (i = 0; i < 256; i++) |
| 530 | rand[i] = arc4random(); |
| 531 | RAND_seed(rand, sizeof(rand)); |
| 532 | |
| 533 | /* Demote the private keys to public keys. */ |
| 534 | demote_sensitive_data(); |
| 535 | |
Ben Lindstrom | c743134 | 2002-03-22 03:11:49 +0000 | [diff] [blame^] | 536 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
| 537 | fatal("%s: no user", SSH_PRIVSEP_USER); |
| 538 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
| 539 | endpwent(); |
| 540 | |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 541 | /* Change our root directory*/ |
Ben Lindstrom | 7a7edf7 | 2002-03-22 02:42:37 +0000 | [diff] [blame] | 542 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
| 543 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, |
| 544 | strerror(errno)); |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 545 | if (chdir("/") == -1) |
| 546 | fatal("chdir(/)"); |
Ben Lindstrom | 6328ab3 | 2002-03-22 02:54:23 +0000 | [diff] [blame] | 547 | |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 548 | /* Drop our privileges */ |
Ben Lindstrom | c743134 | 2002-03-22 03:11:49 +0000 | [diff] [blame^] | 549 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
| 550 | (u_int)pw->pw_gid); |
| 551 | do_setusercontext(pw); |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 552 | } |
| 553 | |
Ben Lindstrom | 0810519 | 2002-03-22 02:50:06 +0000 | [diff] [blame] | 554 | static void |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 555 | privsep_postauth(Authctxt *authctxt, pid_t pid) |
| 556 | { |
| 557 | extern Authctxt *x_authctxt; |
| 558 | int status; |
| 559 | |
| 560 | /* Wait for the child's exit status */ |
| 561 | waitpid(pid, &status, 0); |
| 562 | |
| 563 | /* XXX - Remote port forwarding */ |
| 564 | x_authctxt = authctxt; |
| 565 | |
| 566 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
| 567 | /* File descriptor passing is broken or root login */ |
| 568 | monitor_apply_keystate(monitor); |
| 569 | use_privsep = 0; |
| 570 | return; |
| 571 | } |
Ben Lindstrom | 6328ab3 | 2002-03-22 02:54:23 +0000 | [diff] [blame] | 572 | |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 573 | /* Authentication complete */ |
| 574 | alarm(0); |
| 575 | if (startup_pipe != -1) { |
| 576 | close(startup_pipe); |
| 577 | startup_pipe = -1; |
| 578 | } |
| 579 | |
| 580 | /* New socket pair */ |
| 581 | monitor_reinit(monitor); |
| 582 | |
| 583 | monitor->m_pid = fork(); |
| 584 | if (monitor->m_pid == -1) |
| 585 | fatal("fork of unprivileged child failed"); |
| 586 | else if (monitor->m_pid != 0) { |
| 587 | debug2("User child is on pid %d", pid); |
| 588 | close(monitor->m_recvfd); |
| 589 | monitor_child_postauth(monitor); |
| 590 | |
| 591 | /* NEVERREACHED */ |
| 592 | exit(0); |
| 593 | } |
| 594 | |
| 595 | close(monitor->m_sendfd); |
| 596 | |
| 597 | /* Demote the private keys to public keys. */ |
| 598 | demote_sensitive_data(); |
| 599 | |
| 600 | /* Drop privileges */ |
| 601 | do_setusercontext(authctxt->pw); |
| 602 | |
| 603 | /* It is safe now to apply the key state */ |
| 604 | monitor_apply_keystate(monitor); |
| 605 | } |
| 606 | |
| 607 | |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 608 | static char * |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 609 | list_hostkey_types(void) |
| 610 | { |
Damien Miller | 0e3b872 | 2002-01-22 23:26:38 +1100 | [diff] [blame] | 611 | Buffer b; |
| 612 | char *p; |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 613 | int i; |
Damien Miller | 0e3b872 | 2002-01-22 23:26:38 +1100 | [diff] [blame] | 614 | |
| 615 | buffer_init(&b); |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 616 | for (i = 0; i < options.num_host_key_files; i++) { |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 617 | Key *key = sensitive_data.host_keys[i]; |
| 618 | if (key == NULL) |
| 619 | continue; |
Ben Lindstrom | 1c37c6a | 2001-12-06 18:00:18 +0000 | [diff] [blame] | 620 | switch (key->type) { |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 621 | case KEY_RSA: |
| 622 | case KEY_DSA: |
Damien Miller | 0e3b872 | 2002-01-22 23:26:38 +1100 | [diff] [blame] | 623 | if (buffer_len(&b) > 0) |
| 624 | buffer_append(&b, ",", 1); |
| 625 | p = key_ssh_name(key); |
| 626 | buffer_append(&b, p, strlen(p)); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 627 | break; |
| 628 | } |
| 629 | } |
Damien Miller | 0e3b872 | 2002-01-22 23:26:38 +1100 | [diff] [blame] | 630 | buffer_append(&b, "\0", 1); |
| 631 | p = xstrdup(buffer_ptr(&b)); |
| 632 | buffer_free(&b); |
| 633 | debug("list_hostkey_types: %s", p); |
| 634 | return p; |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 635 | } |
| 636 | |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 637 | Key * |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 638 | get_hostkey_by_type(int type) |
| 639 | { |
| 640 | int i; |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 641 | for (i = 0; i < options.num_host_key_files; i++) { |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 642 | Key *key = sensitive_data.host_keys[i]; |
| 643 | if (key != NULL && key->type == type) |
| 644 | return key; |
| 645 | } |
| 646 | return NULL; |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 647 | } |
| 648 | |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 649 | Key * |
| 650 | get_hostkey_by_index(int ind) |
| 651 | { |
| 652 | if (ind < 0 || ind >= options.num_host_key_files) |
| 653 | return (NULL); |
| 654 | return (sensitive_data.host_keys[ind]); |
| 655 | } |
| 656 | |
| 657 | int |
| 658 | get_hostkey_index(Key *key) |
| 659 | { |
| 660 | int i; |
| 661 | for (i = 0; i < options.num_host_key_files; i++) { |
| 662 | if (key == sensitive_data.host_keys[i]) |
| 663 | return (i); |
| 664 | } |
| 665 | return (-1); |
| 666 | } |
| 667 | |
Damien Miller | 942da03 | 2000-08-18 13:59:06 +1000 | [diff] [blame] | 668 | /* |
| 669 | * returns 1 if connection should be dropped, 0 otherwise. |
| 670 | * dropping starts at connection #max_startups_begin with a probability |
| 671 | * of (max_startups_rate/100). the probability increases linearly until |
| 672 | * all connections are dropped for startups > max_startups |
| 673 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 674 | static int |
Damien Miller | 942da03 | 2000-08-18 13:59:06 +1000 | [diff] [blame] | 675 | drop_connection(int startups) |
| 676 | { |
| 677 | double p, r; |
| 678 | |
| 679 | if (startups < options.max_startups_begin) |
| 680 | return 0; |
| 681 | if (startups >= options.max_startups) |
| 682 | return 1; |
| 683 | if (options.max_startups_rate == 100) |
| 684 | return 1; |
| 685 | |
| 686 | p = 100 - options.max_startups_rate; |
| 687 | p *= startups - options.max_startups_begin; |
| 688 | p /= (double) (options.max_startups - options.max_startups_begin); |
| 689 | p += options.max_startups_rate; |
| 690 | p /= 100.0; |
| 691 | r = arc4random() / (double) UINT_MAX; |
| 692 | |
| 693 | debug("drop_connection: p %g, r %g", p, r); |
| 694 | return (r < p) ? 1 : 0; |
| 695 | } |
| 696 | |
Ben Lindstrom | ade03f6 | 2001-12-06 18:22:17 +0000 | [diff] [blame] | 697 | static void |
| 698 | usage(void) |
| 699 | { |
| 700 | fprintf(stderr, "sshd version %s\n", SSH_VERSION); |
| 701 | fprintf(stderr, "Usage: %s [options]\n", __progname); |
| 702 | fprintf(stderr, "Options:\n"); |
| 703 | fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE); |
| 704 | fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n"); |
| 705 | fprintf(stderr, " -i Started from inetd\n"); |
| 706 | fprintf(stderr, " -D Do not fork into daemon mode\n"); |
| 707 | fprintf(stderr, " -t Only test configuration file and keys\n"); |
| 708 | fprintf(stderr, " -q Quiet (no logging)\n"); |
| 709 | fprintf(stderr, " -p port Listen on the specified port (default: 22)\n"); |
| 710 | fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n"); |
| 711 | fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n"); |
| 712 | fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n"); |
| 713 | fprintf(stderr, " -h file File from which to read host key (default: %s)\n", |
| 714 | _PATH_HOST_KEY_FILE); |
| 715 | fprintf(stderr, " -u len Maximum hostname length for utmp recording\n"); |
| 716 | fprintf(stderr, " -4 Use IPv4 only\n"); |
| 717 | fprintf(stderr, " -6 Use IPv6 only\n"); |
| 718 | fprintf(stderr, " -o option Process the option as if it was read from a configuration file.\n"); |
| 719 | exit(1); |
| 720 | } |
| 721 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 722 | /* |
| 723 | * Main program for the daemon. |
| 724 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 725 | int |
| 726 | main(int ac, char **av) |
| 727 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 728 | extern char *optarg; |
| 729 | extern int optind; |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 730 | int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1; |
Damien Miller | 166fca8 | 2000-04-20 07:42:21 +1000 | [diff] [blame] | 731 | pid_t pid; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 732 | socklen_t fromlen; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 733 | fd_set *fdset; |
| 734 | struct sockaddr_storage from; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 735 | const char *remote_ip; |
| 736 | int remote_port; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 737 | FILE *f; |
| 738 | struct linger linger; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 739 | struct addrinfo *ai; |
| 740 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; |
| 741 | int listen_sock, maxfd; |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 742 | int startup_p[2]; |
| 743 | int startups = 0; |
Ben Lindstrom | 73ab9ba | 2002-03-22 01:27:35 +0000 | [diff] [blame] | 744 | Authctxt *authctxt; |
Ben Lindstrom | d0fca42 | 2001-03-26 13:44:06 +0000 | [diff] [blame] | 745 | Key *key; |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 746 | int ret, key_used = 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 747 | |
Ben Lindstrom | 49a79c0 | 2000-11-17 03:47:20 +0000 | [diff] [blame] | 748 | __progname = get_progname(av[0]); |
Damien Miller | f9b625c | 2000-07-09 22:42:32 +1000 | [diff] [blame] | 749 | init_rng(); |
| 750 | |
Kevin Steves | ec84dc1 | 2000-12-13 17:45:15 +0000 | [diff] [blame] | 751 | /* Save argv. */ |
Damien Miller | b8c656e | 2000-06-28 15:22:41 +1000 | [diff] [blame] | 752 | saved_argc = ac; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 753 | saved_argv = av; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 754 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 755 | /* Initialize configuration options to their default values. */ |
| 756 | initialize_server_options(&options); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 757 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 758 | /* Parse command-line arguments. */ |
Ben Lindstrom | ade03f6 | 2001-12-06 18:22:17 +0000 | [diff] [blame] | 759 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:o:dDeiqtQ46")) != -1) { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 760 | switch (opt) { |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 761 | case '4': |
| 762 | IPv4or6 = AF_INET; |
| 763 | break; |
| 764 | case '6': |
| 765 | IPv4or6 = AF_INET6; |
| 766 | break; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 767 | case 'f': |
| 768 | config_file_name = optarg; |
| 769 | break; |
| 770 | case 'd': |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 771 | if (0 == debug_flag) { |
| 772 | debug_flag = 1; |
| 773 | options.log_level = SYSLOG_LEVEL_DEBUG1; |
| 774 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) { |
| 775 | options.log_level++; |
| 776 | } else { |
| 777 | fprintf(stderr, "Too high debugging level.\n"); |
| 778 | exit(1); |
| 779 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 780 | break; |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 781 | case 'D': |
| 782 | no_daemon_flag = 1; |
| 783 | break; |
Ben Lindstrom | 9fce9f0 | 2001-04-11 23:10:09 +0000 | [diff] [blame] | 784 | case 'e': |
| 785 | log_stderr = 1; |
| 786 | break; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 787 | case 'i': |
| 788 | inetd_flag = 1; |
| 789 | break; |
| 790 | case 'Q': |
Ben Lindstrom | d539020 | 2001-01-29 08:07:43 +0000 | [diff] [blame] | 791 | /* ignored */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 792 | break; |
| 793 | case 'q': |
| 794 | options.log_level = SYSLOG_LEVEL_QUIET; |
| 795 | break; |
| 796 | case 'b': |
| 797 | options.server_key_bits = atoi(optarg); |
| 798 | break; |
| 799 | case 'p': |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 800 | options.ports_from_cmdline = 1; |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 801 | if (options.num_ports >= MAX_PORTS) { |
| 802 | fprintf(stderr, "too many ports.\n"); |
| 803 | exit(1); |
| 804 | } |
Ben Lindstrom | 19066a1 | 2001-04-12 23:39:26 +0000 | [diff] [blame] | 805 | options.ports[options.num_ports++] = a2port(optarg); |
| 806 | if (options.ports[options.num_ports-1] == 0) { |
| 807 | fprintf(stderr, "Bad port number.\n"); |
| 808 | exit(1); |
| 809 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 810 | break; |
| 811 | case 'g': |
Ben Lindstrom | 1bda4c8 | 2001-06-05 19:59:08 +0000 | [diff] [blame] | 812 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
| 813 | fprintf(stderr, "Invalid login grace time.\n"); |
| 814 | exit(1); |
| 815 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 816 | break; |
| 817 | case 'k': |
Ben Lindstrom | 1bda4c8 | 2001-06-05 19:59:08 +0000 | [diff] [blame] | 818 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
| 819 | fprintf(stderr, "Invalid key regeneration interval.\n"); |
| 820 | exit(1); |
| 821 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 822 | break; |
| 823 | case 'h': |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 824 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
| 825 | fprintf(stderr, "too many host keys.\n"); |
| 826 | exit(1); |
| 827 | } |
| 828 | options.host_key_files[options.num_host_key_files++] = optarg; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 829 | break; |
| 830 | case 'V': |
| 831 | client_version_string = optarg; |
| 832 | /* only makes sense with inetd_flag, i.e. no listen() */ |
| 833 | inetd_flag = 1; |
| 834 | break; |
Ben Lindstrom | 794325a | 2001-08-06 21:09:07 +0000 | [diff] [blame] | 835 | case 't': |
| 836 | test_flag = 1; |
| 837 | break; |
Damien Miller | 942da03 | 2000-08-18 13:59:06 +1000 | [diff] [blame] | 838 | case 'u': |
| 839 | utmp_len = atoi(optarg); |
| 840 | break; |
Ben Lindstrom | ade03f6 | 2001-12-06 18:22:17 +0000 | [diff] [blame] | 841 | case 'o': |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 842 | if (process_server_config_line(&options, optarg, |
Ben Lindstrom | ade03f6 | 2001-12-06 18:22:17 +0000 | [diff] [blame] | 843 | "command-line", 0) != 0) |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 844 | exit(1); |
Ben Lindstrom | ade03f6 | 2001-12-06 18:22:17 +0000 | [diff] [blame] | 845 | break; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 846 | case '?': |
| 847 | default: |
Ben Lindstrom | ade03f6 | 2001-12-06 18:22:17 +0000 | [diff] [blame] | 848 | usage(); |
| 849 | break; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 850 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 851 | } |
Ben Lindstrom | 425fb02 | 2001-03-29 00:31:20 +0000 | [diff] [blame] | 852 | SSLeay_add_all_algorithms(); |
Ben Lindstrom | 908afed | 2001-10-03 17:34:59 +0000 | [diff] [blame] | 853 | channel_set_af(IPv4or6); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 854 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 855 | /* |
| 856 | * Force logging to stderr until we have loaded the private host |
| 857 | * key (unless started from inetd) |
| 858 | */ |
Kevin Steves | ec84dc1 | 2000-12-13 17:45:15 +0000 | [diff] [blame] | 859 | log_init(__progname, |
Damien Miller | 5aa5d78 | 2002-02-08 22:01:54 +1100 | [diff] [blame] | 860 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
| 861 | SYSLOG_LEVEL_INFO : options.log_level, |
| 862 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? |
| 863 | SYSLOG_FACILITY_AUTH : options.log_facility, |
Ben Lindstrom | d539020 | 2001-01-29 08:07:43 +0000 | [diff] [blame] | 864 | !inetd_flag); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 865 | |
Ben Lindstrom | 6db66ff | 2001-08-06 23:29:16 +0000 | [diff] [blame] | 866 | #ifdef _CRAY |
| 867 | /* Cray can define user privs drop all prives now! |
| 868 | * Not needed on PRIV_SU systems! |
| 869 | */ |
| 870 | drop_cray_privs(); |
| 871 | #endif |
| 872 | |
Damien Miller | 60bc517 | 2001-03-19 09:38:15 +1100 | [diff] [blame] | 873 | seed_rng(); |
| 874 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 875 | /* Read server configuration options from the configuration file. */ |
| 876 | read_server_config(&options, config_file_name); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 877 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 878 | /* Fill in default values for those options not explicitly set. */ |
| 879 | fill_default_server_options(&options); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 880 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 881 | /* Check that there are no remaining arguments. */ |
| 882 | if (optind < ac) { |
| 883 | fprintf(stderr, "Extra argument %s.\n", av[optind]); |
| 884 | exit(1); |
| 885 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 886 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 887 | debug("sshd version %.100s", SSH_VERSION); |
Damien Miller | 2ccf661 | 1999-11-15 15:25:10 +1100 | [diff] [blame] | 888 | |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 889 | /* load private host keys */ |
| 890 | sensitive_data.host_keys = xmalloc(options.num_host_key_files*sizeof(Key*)); |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 891 | for (i = 0; i < options.num_host_key_files; i++) |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 892 | sensitive_data.host_keys[i] = NULL; |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 893 | sensitive_data.server_key = NULL; |
| 894 | sensitive_data.ssh1_host_key = NULL; |
| 895 | sensitive_data.have_ssh1_key = 0; |
| 896 | sensitive_data.have_ssh2_key = 0; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 897 | |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 898 | for (i = 0; i < options.num_host_key_files; i++) { |
Ben Lindstrom | d0fca42 | 2001-03-26 13:44:06 +0000 | [diff] [blame] | 899 | key = key_load_private(options.host_key_files[i], "", NULL); |
| 900 | sensitive_data.host_keys[i] = key; |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 901 | if (key == NULL) { |
Ben Lindstrom | 15f3386 | 2001-04-16 02:00:02 +0000 | [diff] [blame] | 902 | error("Could not load host key: %s", |
| 903 | options.host_key_files[i]); |
Ben Lindstrom | d0fca42 | 2001-03-26 13:44:06 +0000 | [diff] [blame] | 904 | sensitive_data.host_keys[i] = NULL; |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 905 | continue; |
| 906 | } |
Ben Lindstrom | 1c37c6a | 2001-12-06 18:00:18 +0000 | [diff] [blame] | 907 | switch (key->type) { |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 908 | case KEY_RSA1: |
| 909 | sensitive_data.ssh1_host_key = key; |
| 910 | sensitive_data.have_ssh1_key = 1; |
| 911 | break; |
| 912 | case KEY_RSA: |
| 913 | case KEY_DSA: |
| 914 | sensitive_data.have_ssh2_key = 1; |
| 915 | break; |
| 916 | } |
Ben Lindstrom | d0fca42 | 2001-03-26 13:44:06 +0000 | [diff] [blame] | 917 | debug("private host key: #%d type %d %s", i, key->type, |
| 918 | key_type(key)); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 919 | } |
| 920 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { |
| 921 | log("Disabling protocol version 1. Could not load host key"); |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 922 | options.protocol &= ~SSH_PROTO_1; |
| 923 | } |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 924 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { |
| 925 | log("Disabling protocol version 2. Could not load host key"); |
| 926 | options.protocol &= ~SSH_PROTO_2; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 927 | } |
Kevin Steves | adf74cd | 2001-02-05 14:22:50 +0000 | [diff] [blame] | 928 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
Ben Lindstrom | 6df8ef4 | 2001-03-05 07:47:23 +0000 | [diff] [blame] | 929 | log("sshd: no hostkeys available -- exiting."); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 930 | exit(1); |
| 931 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 932 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 933 | /* Check certain values for sanity. */ |
| 934 | if (options.protocol & SSH_PROTO_1) { |
| 935 | if (options.server_key_bits < 512 || |
| 936 | options.server_key_bits > 32768) { |
| 937 | fprintf(stderr, "Bad server key size.\n"); |
| 938 | exit(1); |
| 939 | } |
| 940 | /* |
| 941 | * Check that server and host key lengths differ sufficiently. This |
| 942 | * is necessary to make double encryption work with rsaref. Oh, I |
| 943 | * hate software patents. I dont know if this can go? Niels |
| 944 | */ |
| 945 | if (options.server_key_bits > |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 946 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - SSH_KEY_BITS_RESERVED && |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 947 | options.server_key_bits < |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 948 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 949 | options.server_key_bits = |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 950 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 951 | debug("Forcing server key to %d bits to make it differ from host key.", |
| 952 | options.server_key_bits); |
| 953 | } |
| 954 | } |
| 955 | |
Ben Lindstrom | 794325a | 2001-08-06 21:09:07 +0000 | [diff] [blame] | 956 | /* Configuration looks good, so exit if in test mode. */ |
| 957 | if (test_flag) |
| 958 | exit(0); |
| 959 | |
Damien Miller | 78315eb | 2000-09-29 23:01:36 +1100 | [diff] [blame] | 960 | #ifdef HAVE_SCO_PROTECTED_PW |
| 961 | (void) set_auth_parameters(ac, av); |
| 962 | #endif |
| 963 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 964 | /* Initialize the log (it is reinitialized below in case we forked). */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 965 | if (debug_flag && !inetd_flag) |
| 966 | log_stderr = 1; |
Kevin Steves | ec84dc1 | 2000-12-13 17:45:15 +0000 | [diff] [blame] | 967 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 968 | |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 969 | /* |
| 970 | * If not in debugging mode, and not started from inetd, disconnect |
| 971 | * from the controlling terminal, and fork. The original process |
| 972 | * exits. |
| 973 | */ |
Ben Lindstrom | c72745a | 2000-12-02 19:03:54 +0000 | [diff] [blame] | 974 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 975 | #ifdef TIOCNOTTY |
| 976 | int fd; |
| 977 | #endif /* TIOCNOTTY */ |
| 978 | if (daemon(0, 0) < 0) |
| 979 | fatal("daemon() failed: %.200s", strerror(errno)); |
| 980 | |
| 981 | /* Disconnect from the controlling tty. */ |
| 982 | #ifdef TIOCNOTTY |
Ben Lindstrom | 31ca54a | 2001-02-09 02:11:24 +0000 | [diff] [blame] | 983 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 984 | if (fd >= 0) { |
| 985 | (void) ioctl(fd, TIOCNOTTY, NULL); |
| 986 | close(fd); |
| 987 | } |
| 988 | #endif /* TIOCNOTTY */ |
| 989 | } |
| 990 | /* Reinitialize the log (because of the fork above). */ |
Kevin Steves | ec84dc1 | 2000-12-13 17:45:15 +0000 | [diff] [blame] | 991 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 992 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 993 | /* Initialize the random number generator. */ |
| 994 | arc4random_stir(); |
| 995 | |
| 996 | /* Chdir to the root directory so that the current disk can be |
| 997 | unmounted if desired. */ |
| 998 | chdir("/"); |
Damien Miller | 9f0f5c6 | 2001-12-21 14:45:46 +1100 | [diff] [blame] | 999 | |
Ben Lindstrom | de71cda | 2001-03-24 00:43:26 +0000 | [diff] [blame] | 1000 | /* ignore SIGPIPE */ |
| 1001 | signal(SIGPIPE, SIG_IGN); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1002 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1003 | /* Start listening for a socket, unless started from inetd. */ |
| 1004 | if (inetd_flag) { |
Ben Lindstrom | 206941f | 2001-04-15 14:27:16 +0000 | [diff] [blame] | 1005 | int s1; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1006 | s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */ |
Ben Lindstrom | 206941f | 2001-04-15 14:27:16 +0000 | [diff] [blame] | 1007 | dup(s1); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1008 | sock_in = dup(0); |
| 1009 | sock_out = dup(1); |
Damien Miller | 994cf14 | 2000-07-21 10:19:44 +1000 | [diff] [blame] | 1010 | startup_pipe = -1; |
Damien Miller | eba71ba | 2000-04-29 23:57:08 +1000 | [diff] [blame] | 1011 | /* |
| 1012 | * We intentionally do not close the descriptors 0, 1, and 2 |
| 1013 | * as our code for setting the descriptors won\'t work if |
| 1014 | * ttyfd happens to be one of those. |
| 1015 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1016 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 1017 | if (options.protocol & SSH_PROTO_1) |
Ben Lindstrom | ca42d5f | 2001-03-09 18:25:32 +0000 | [diff] [blame] | 1018 | generate_ephemeral_server_key(); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1019 | } else { |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1020 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
| 1021 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) |
| 1022 | continue; |
| 1023 | if (num_listen_socks >= MAX_LISTEN_SOCKS) |
| 1024 | fatal("Too many listen sockets. " |
| 1025 | "Enlarge MAX_LISTEN_SOCKS"); |
| 1026 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, |
| 1027 | ntop, sizeof(ntop), strport, sizeof(strport), |
| 1028 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { |
| 1029 | error("getnameinfo failed"); |
| 1030 | continue; |
| 1031 | } |
| 1032 | /* Create socket for listening. */ |
| 1033 | listen_sock = socket(ai->ai_family, SOCK_STREAM, 0); |
| 1034 | if (listen_sock < 0) { |
| 1035 | /* kernel may not support ipv6 */ |
| 1036 | verbose("socket: %.100s", strerror(errno)); |
| 1037 | continue; |
| 1038 | } |
| 1039 | if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) { |
| 1040 | error("listen_sock O_NONBLOCK: %s", strerror(errno)); |
| 1041 | close(listen_sock); |
| 1042 | continue; |
| 1043 | } |
| 1044 | /* |
| 1045 | * Set socket options. We try to make the port |
| 1046 | * reusable and have it close as fast as possible |
| 1047 | * without waiting in unnecessary wait states on |
| 1048 | * close. |
| 1049 | */ |
| 1050 | setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
Ben Lindstrom | 733a235 | 2002-03-05 01:31:28 +0000 | [diff] [blame] | 1051 | &on, sizeof(on)); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1052 | linger.l_onoff = 1; |
| 1053 | linger.l_linger = 5; |
| 1054 | setsockopt(listen_sock, SOL_SOCKET, SO_LINGER, |
Ben Lindstrom | 733a235 | 2002-03-05 01:31:28 +0000 | [diff] [blame] | 1055 | &linger, sizeof(linger)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1056 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1057 | debug("Bind to port %s on %s.", strport, ntop); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1058 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1059 | /* Bind the socket to the desired port. */ |
Damien Miller | 0a4e27d | 2001-02-18 12:36:39 +1100 | [diff] [blame] | 1060 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
| 1061 | if (!ai->ai_next) |
| 1062 | error("Bind to port %s on %s failed: %.200s.", |
| 1063 | strport, ntop, strerror(errno)); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1064 | close(listen_sock); |
| 1065 | continue; |
| 1066 | } |
| 1067 | listen_socks[num_listen_socks] = listen_sock; |
| 1068 | num_listen_socks++; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1069 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1070 | /* Start listening on the port. */ |
| 1071 | log("Server listening on %s port %s.", ntop, strport); |
| 1072 | if (listen(listen_sock, 5) < 0) |
| 1073 | fatal("listen: %.100s", strerror(errno)); |
| 1074 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1075 | } |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1076 | freeaddrinfo(options.listen_addrs); |
| 1077 | |
| 1078 | if (!num_listen_socks) |
| 1079 | fatal("Cannot bind any address."); |
| 1080 | |
Ben Lindstrom | 9809786 | 2001-06-25 05:10:20 +0000 | [diff] [blame] | 1081 | if (options.protocol & SSH_PROTO_1) |
| 1082 | generate_ephemeral_server_key(); |
| 1083 | |
| 1084 | /* |
| 1085 | * Arrange to restart on SIGHUP. The handler needs |
| 1086 | * listen_sock. |
| 1087 | */ |
| 1088 | signal(SIGHUP, sighup_handler); |
| 1089 | |
| 1090 | signal(SIGTERM, sigterm_handler); |
| 1091 | signal(SIGQUIT, sigterm_handler); |
| 1092 | |
| 1093 | /* Arrange SIGCHLD to be caught. */ |
| 1094 | signal(SIGCHLD, main_sigchld_handler); |
| 1095 | |
| 1096 | /* Write out the pid file after the sigterm handler is setup */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1097 | if (!debug_flag) { |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1098 | /* |
Ben Lindstrom | 7ad9710 | 2000-12-06 01:42:49 +0000 | [diff] [blame] | 1099 | * Record our pid in /var/run/sshd.pid to make it |
| 1100 | * easier to kill the correct sshd. We don't want to |
| 1101 | * do this before the bind above because the bind will |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1102 | * fail if there already is a daemon, and this will |
| 1103 | * overwrite any old pid in the file. |
| 1104 | */ |
Damien Miller | bac2d8a | 2000-09-05 16:13:06 +1100 | [diff] [blame] | 1105 | f = fopen(options.pid_file, "wb"); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1106 | if (f) { |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 1107 | fprintf(f, "%u\n", (u_int) getpid()); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1108 | fclose(f); |
| 1109 | } |
| 1110 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1111 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1112 | /* setup fd set for listen */ |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1113 | fdset = NULL; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1114 | maxfd = 0; |
| 1115 | for (i = 0; i < num_listen_socks; i++) |
| 1116 | if (listen_socks[i] > maxfd) |
| 1117 | maxfd = listen_socks[i]; |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1118 | /* pipes connected to unauthenticated childs */ |
| 1119 | startup_pipes = xmalloc(options.max_startups * sizeof(int)); |
| 1120 | for (i = 0; i < options.max_startups; i++) |
| 1121 | startup_pipes[i] = -1; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1122 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1123 | /* |
| 1124 | * Stay listening for connections until the system crashes or |
| 1125 | * the daemon is killed with a signal. |
| 1126 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1127 | for (;;) { |
| 1128 | if (received_sighup) |
| 1129 | sighup_restart(); |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1130 | if (fdset != NULL) |
| 1131 | xfree(fdset); |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame] | 1132 | fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask); |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1133 | fdset = (fd_set *)xmalloc(fdsetsz); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1134 | memset(fdset, 0, fdsetsz); |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1135 | |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1136 | for (i = 0; i < num_listen_socks; i++) |
| 1137 | FD_SET(listen_socks[i], fdset); |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1138 | for (i = 0; i < options.max_startups; i++) |
| 1139 | if (startup_pipes[i] != -1) |
| 1140 | FD_SET(startup_pipes[i], fdset); |
| 1141 | |
| 1142 | /* Wait in select until there is a connection. */ |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 1143 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); |
| 1144 | if (ret < 0 && errno != EINTR) |
| 1145 | error("select: %.100s", strerror(errno)); |
Ben Lindstrom | ec46e0b | 2001-06-09 01:27:31 +0000 | [diff] [blame] | 1146 | if (received_sigterm) { |
| 1147 | log("Received signal %d; terminating.", |
Ben Lindstrom | f8f065b | 2001-12-06 17:52:16 +0000 | [diff] [blame] | 1148 | (int) received_sigterm); |
Ben Lindstrom | ec46e0b | 2001-06-09 01:27:31 +0000 | [diff] [blame] | 1149 | close_listen_socks(); |
| 1150 | unlink(options.pid_file); |
| 1151 | exit(255); |
| 1152 | } |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 1153 | if (key_used && key_do_regen) { |
Ben Lindstrom | ca42d5f | 2001-03-09 18:25:32 +0000 | [diff] [blame] | 1154 | generate_ephemeral_server_key(); |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 1155 | key_used = 0; |
| 1156 | key_do_regen = 0; |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1157 | } |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 1158 | if (ret < 0) |
| 1159 | continue; |
| 1160 | |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1161 | for (i = 0; i < options.max_startups; i++) |
| 1162 | if (startup_pipes[i] != -1 && |
| 1163 | FD_ISSET(startup_pipes[i], fdset)) { |
| 1164 | /* |
| 1165 | * the read end of the pipe is ready |
| 1166 | * if the child has closed the pipe |
Ben Lindstrom | 4dccfa5 | 2000-12-28 16:40:05 +0000 | [diff] [blame] | 1167 | * after successful authentication |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1168 | * or if the child has died |
| 1169 | */ |
| 1170 | close(startup_pipes[i]); |
| 1171 | startup_pipes[i] = -1; |
| 1172 | startups--; |
| 1173 | } |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1174 | for (i = 0; i < num_listen_socks; i++) { |
| 1175 | if (!FD_ISSET(listen_socks[i], fdset)) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1176 | continue; |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1177 | fromlen = sizeof(from); |
| 1178 | newsock = accept(listen_socks[i], (struct sockaddr *)&from, |
| 1179 | &fromlen); |
| 1180 | if (newsock < 0) { |
| 1181 | if (errno != EINTR && errno != EWOULDBLOCK) |
| 1182 | error("accept: %.100s", strerror(errno)); |
| 1183 | continue; |
| 1184 | } |
| 1185 | if (fcntl(newsock, F_SETFL, 0) < 0) { |
| 1186 | error("newsock del O_NONBLOCK: %s", strerror(errno)); |
Damien Miller | 72c336d | 2001-12-21 12:44:28 +1100 | [diff] [blame] | 1187 | close(newsock); |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1188 | continue; |
| 1189 | } |
Damien Miller | 942da03 | 2000-08-18 13:59:06 +1000 | [diff] [blame] | 1190 | if (drop_connection(startups) == 1) { |
| 1191 | debug("drop connection #%d", startups); |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1192 | close(newsock); |
| 1193 | continue; |
| 1194 | } |
| 1195 | if (pipe(startup_p) == -1) { |
| 1196 | close(newsock); |
| 1197 | continue; |
| 1198 | } |
| 1199 | |
| 1200 | for (j = 0; j < options.max_startups; j++) |
| 1201 | if (startup_pipes[j] == -1) { |
| 1202 | startup_pipes[j] = startup_p[0]; |
| 1203 | if (maxfd < startup_p[0]) |
| 1204 | maxfd = startup_p[0]; |
| 1205 | startups++; |
| 1206 | break; |
| 1207 | } |
Kevin Steves | ef4eea9 | 2001-02-05 12:42:17 +0000 | [diff] [blame] | 1208 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1209 | /* |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1210 | * Got connection. Fork a child to handle it, unless |
| 1211 | * we are in debugging mode. |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1212 | */ |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1213 | if (debug_flag) { |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1214 | /* |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1215 | * In debugging mode. Close the listening |
| 1216 | * socket, and start processing the |
| 1217 | * connection without forking. |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1218 | */ |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1219 | debug("Server will not fork when running in debugging mode."); |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1220 | close_listen_socks(); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1221 | sock_in = newsock; |
| 1222 | sock_out = newsock; |
Damien Miller | 4d97ba2 | 2000-07-11 18:15:50 +1000 | [diff] [blame] | 1223 | startup_pipe = -1; |
Damien Miller | 182ee6e | 2000-07-12 09:45:27 +1000 | [diff] [blame] | 1224 | pid = getpid(); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1225 | break; |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1226 | } else { |
| 1227 | /* |
| 1228 | * Normal production daemon. Fork, and have |
| 1229 | * the child process the connection. The |
| 1230 | * parent continues listening. |
| 1231 | */ |
| 1232 | if ((pid = fork()) == 0) { |
| 1233 | /* |
| 1234 | * Child. Close the listening and max_startup |
| 1235 | * sockets. Start using the accepted socket. |
| 1236 | * Reinitialize logging (since our pid has |
| 1237 | * changed). We break out of the loop to handle |
| 1238 | * the connection. |
| 1239 | */ |
| 1240 | startup_pipe = startup_p[1]; |
Ben Lindstrom | d84df98 | 2001-12-06 16:35:40 +0000 | [diff] [blame] | 1241 | close_startup_pipes(); |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1242 | close_listen_socks(); |
| 1243 | sock_in = newsock; |
| 1244 | sock_out = newsock; |
Kevin Steves | ec84dc1 | 2000-12-13 17:45:15 +0000 | [diff] [blame] | 1245 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1246 | break; |
| 1247 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1248 | } |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1249 | |
| 1250 | /* Parent. Stay in the loop. */ |
| 1251 | if (pid < 0) |
| 1252 | error("fork: %.100s", strerror(errno)); |
| 1253 | else |
| 1254 | debug("Forked child %d.", pid); |
| 1255 | |
| 1256 | close(startup_p[1]); |
| 1257 | |
| 1258 | /* Mark that the key has been used (it was "given" to the child). */ |
Ben Lindstrom | db65e8f | 2001-01-19 04:26:52 +0000 | [diff] [blame] | 1259 | if ((options.protocol & SSH_PROTO_1) && |
| 1260 | key_used == 0) { |
| 1261 | /* Schedule server key regeneration alarm. */ |
| 1262 | signal(SIGALRM, key_regeneration_alarm); |
| 1263 | alarm(options.key_regeneration_time); |
| 1264 | key_used = 1; |
| 1265 | } |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 1266 | |
| 1267 | arc4random_stir(); |
| 1268 | |
| 1269 | /* Close the new socket (the child is now taking care of it). */ |
| 1270 | close(newsock); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1271 | } |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1272 | /* child process check (or debug mode) */ |
| 1273 | if (num_listen_socks < 0) |
| 1274 | break; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1275 | } |
| 1276 | } |
| 1277 | |
| 1278 | /* This is the child processing a new connection. */ |
| 1279 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1280 | /* |
| 1281 | * Disable the key regeneration alarm. We will not regenerate the |
| 1282 | * key since we are no longer in a position to give it to anyone. We |
| 1283 | * will not restart on SIGHUP since it no longer makes sense. |
| 1284 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1285 | alarm(0); |
| 1286 | signal(SIGALRM, SIG_DFL); |
| 1287 | signal(SIGHUP, SIG_DFL); |
| 1288 | signal(SIGTERM, SIG_DFL); |
| 1289 | signal(SIGQUIT, SIG_DFL); |
| 1290 | signal(SIGCHLD, SIG_DFL); |
Damien Miller | 4e0f5e1 | 2000-08-29 11:05:50 +1100 | [diff] [blame] | 1291 | signal(SIGINT, SIG_DFL); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1292 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1293 | /* |
| 1294 | * Set socket options for the connection. We want the socket to |
| 1295 | * close as fast as possible without waiting for anything. If the |
| 1296 | * connection is not a socket, these will do nothing. |
| 1297 | */ |
| 1298 | /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1299 | linger.l_onoff = 1; |
| 1300 | linger.l_linger = 5; |
Ben Lindstrom | 733a235 | 2002-03-05 01:31:28 +0000 | [diff] [blame] | 1301 | setsockopt(sock_in, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1302 | |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame] | 1303 | /* Set keepalives if requested. */ |
| 1304 | if (options.keepalives && |
Ben Lindstrom | 733a235 | 2002-03-05 01:31:28 +0000 | [diff] [blame] | 1305 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, |
Ben Lindstrom | bf555ba | 2001-01-18 02:04:35 +0000 | [diff] [blame] | 1306 | sizeof(on)) < 0) |
| 1307 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); |
| 1308 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1309 | /* |
| 1310 | * Register our connection. This turns encryption off because we do |
| 1311 | * not have a key. |
| 1312 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1313 | packet_set_connection(sock_in, sock_out); |
| 1314 | |
| 1315 | remote_port = get_remote_port(); |
| 1316 | remote_ip = get_remote_ipaddr(); |
| 1317 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1318 | #ifdef LIBWRAP |
Damien Miller | 6a4a4b9 | 2001-11-12 11:07:11 +1100 | [diff] [blame] | 1319 | /* Check whether logins are denied from this host. */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1320 | { |
| 1321 | struct request_info req; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1322 | |
Ben Lindstrom | ce89dac | 2001-09-12 16:58:04 +0000 | [diff] [blame] | 1323 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1324 | fromhost(&req); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1325 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1326 | if (!hosts_access(&req)) { |
Damien Miller | 6a4a4b9 | 2001-11-12 11:07:11 +1100 | [diff] [blame] | 1327 | debug("Connection refused by tcp wrapper"); |
Ben Lindstrom | 7de696e | 2001-03-29 00:45:12 +0000 | [diff] [blame] | 1328 | refuse(&req); |
Damien Miller | 6a4a4b9 | 2001-11-12 11:07:11 +1100 | [diff] [blame] | 1329 | /* NOTREACHED */ |
| 1330 | fatal("libwrap refuse returns"); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1331 | } |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1332 | } |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1333 | #endif /* LIBWRAP */ |
Damien Miller | 6a4a4b9 | 2001-11-12 11:07:11 +1100 | [diff] [blame] | 1334 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1335 | /* Log the connection. */ |
| 1336 | verbose("Connection from %.500s port %d", remote_ip, remote_port); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1337 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1338 | /* |
| 1339 | * We don\'t want to listen forever unless the other side |
| 1340 | * successfully authenticates itself. So we set up an alarm which is |
| 1341 | * cleared after successful authentication. A limit of zero |
| 1342 | * indicates no limit. Note that we don\'t set the alarm in debugging |
| 1343 | * mode; it is just annoying to have the server exit just when you |
| 1344 | * are about to discover the bug. |
| 1345 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1346 | signal(SIGALRM, grace_alarm_handler); |
| 1347 | if (!debug_flag) |
| 1348 | alarm(options.login_grace_time); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1349 | |
Damien Miller | b38eff8 | 2000-04-01 11:09:21 +1000 | [diff] [blame] | 1350 | sshd_exchange_identification(sock_in, sock_out); |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1351 | /* |
Kevin Steves | fcec7f8 | 2000-12-15 19:55:48 +0000 | [diff] [blame] | 1352 | * Check that the connection comes from a privileged port. |
| 1353 | * Rhosts-Authentication only makes sense from priviledged |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1354 | * programs. Of course, if the intruder has root access on his local |
| 1355 | * machine, he can connect from any port. So do not use these |
| 1356 | * authentication methods from machines that you do not trust. |
| 1357 | */ |
Damien Miller | 654c03f | 2002-02-13 13:54:44 +1100 | [diff] [blame] | 1358 | if (options.rhosts_authentication && |
| 1359 | (remote_port >= IPPORT_RESERVED || |
| 1360 | remote_port < IPPORT_RESERVED / 2)) { |
Kevin Steves | fcec7f8 | 2000-12-15 19:55:48 +0000 | [diff] [blame] | 1361 | debug("Rhosts Authentication disabled, " |
Damien Miller | 00b6164 | 2001-11-12 10:51:23 +1100 | [diff] [blame] | 1362 | "originating port %d not trusted.", remote_port); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1363 | options.rhosts_authentication = 0; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1364 | } |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 1365 | #if defined(KRB4) && !defined(KRB5) |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1366 | if (!packet_connection_is_ipv4() && |
| 1367 | options.kerberos_authentication) { |
| 1368 | debug("Kerberos Authentication disabled, only available for IPv4."); |
| 1369 | options.kerberos_authentication = 0; |
| 1370 | } |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 1371 | #endif /* KRB4 && !KRB5 */ |
Ben Lindstrom | f79aeff | 2001-02-10 21:27:11 +0000 | [diff] [blame] | 1372 | #ifdef AFS |
| 1373 | /* If machine has AFS, set process authentication group. */ |
| 1374 | if (k_hasafs()) { |
| 1375 | k_setpag(); |
| 1376 | k_unlog(); |
| 1377 | } |
| 1378 | #endif /* AFS */ |
Damien Miller | 34132e5 | 2000-01-14 15:45:46 +1100 | [diff] [blame] | 1379 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1380 | packet_set_nonblocking(); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1381 | |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 1382 | if (!use_privsep) |
| 1383 | goto skip_privilegeseparation; |
Ben Lindstrom | 6328ab3 | 2002-03-22 02:54:23 +0000 | [diff] [blame] | 1384 | |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 1385 | /* Set up unprivileged child process to deal with network data */ |
| 1386 | monitor = monitor_init(); |
| 1387 | /* Store a pointer to the kex for later rekeying */ |
| 1388 | monitor->m_pkex = &xxx_kex; |
| 1389 | |
| 1390 | pid = fork(); |
| 1391 | if (pid == -1) |
| 1392 | fatal("fork of unprivileged child failed"); |
| 1393 | else if (pid != 0) { |
| 1394 | debug2("Network child is on pid %d", pid); |
| 1395 | |
| 1396 | close(monitor->m_recvfd); |
| 1397 | authctxt = monitor_child_preauth(monitor); |
| 1398 | close(monitor->m_sendfd); |
| 1399 | |
| 1400 | /* Sync memory */ |
| 1401 | monitor_sync(monitor); |
| 1402 | goto authenticated; |
| 1403 | } else { |
| 1404 | close(monitor->m_sendfd); |
| 1405 | |
| 1406 | /* Demote the child */ |
| 1407 | if (getuid() == 0 || geteuid() == 0) |
| 1408 | privsep_preauth_child(); |
| 1409 | } |
| 1410 | |
| 1411 | skip_privilegeseparation: |
| 1412 | |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 1413 | /* perform the key exchange */ |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 1414 | /* authenticate user and start session */ |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 1415 | if (compat20) { |
| 1416 | do_ssh2_kex(); |
Ben Lindstrom | 73ab9ba | 2002-03-22 01:27:35 +0000 | [diff] [blame] | 1417 | authctxt = do_authentication2(); |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 1418 | } else { |
| 1419 | do_ssh1_kex(); |
Ben Lindstrom | 73ab9ba | 2002-03-22 01:27:35 +0000 | [diff] [blame] | 1420 | authctxt = do_authentication(); |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 1421 | } |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 1422 | if (use_privsep) |
| 1423 | mm_send_keystate(monitor); |
| 1424 | |
| 1425 | /* If we use privilege separation, the unprivileged child exits */ |
| 1426 | if (use_privsep) |
| 1427 | exit(0); |
| 1428 | |
| 1429 | authenticated: |
Ben Lindstrom | 6328ab3 | 2002-03-22 02:54:23 +0000 | [diff] [blame] | 1430 | /* |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 1431 | * In privilege separation, we fork another child and prepare |
| 1432 | * file descriptor passing. |
| 1433 | */ |
| 1434 | if (use_privsep) { |
| 1435 | privsep_postauth(authctxt, pid); |
| 1436 | if (!compat20) |
| 1437 | destroy_sensitive_data(); |
| 1438 | } |
Ben Lindstrom | 73ab9ba | 2002-03-22 01:27:35 +0000 | [diff] [blame] | 1439 | |
| 1440 | /* Perform session preparation. */ |
| 1441 | do_authenticated(authctxt); |
| 1442 | |
Damien Miller | 3a5b023 | 2002-03-13 13:19:42 +1100 | [diff] [blame] | 1443 | /* The connection has been terminated. */ |
| 1444 | verbose("Closing connection to %.100s", remote_ip); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1445 | |
Damien Miller | beb4ba5 | 1999-12-28 15:09:35 +1100 | [diff] [blame] | 1446 | #ifdef USE_PAM |
Damien Miller | e72b7af | 1999-12-30 15:08:44 +1100 | [diff] [blame] | 1447 | finish_pam(); |
Damien Miller | beb4ba5 | 1999-12-28 15:09:35 +1100 | [diff] [blame] | 1448 | #endif /* USE_PAM */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1449 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1450 | packet_close(); |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 1451 | |
| 1452 | if (use_privsep) |
| 1453 | mm_terminate(); |
| 1454 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1455 | exit(0); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1456 | } |
| 1457 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1458 | /* |
Ben Lindstrom | abcb145 | 2002-03-22 01:10:21 +0000 | [diff] [blame] | 1459 | * Decrypt session_key_int using our private server key and private host key |
| 1460 | * (key with larger modulus first). |
| 1461 | */ |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 1462 | int |
Ben Lindstrom | abcb145 | 2002-03-22 01:10:21 +0000 | [diff] [blame] | 1463 | ssh1_session_key(BIGNUM *session_key_int) |
| 1464 | { |
| 1465 | int rsafail = 0; |
| 1466 | |
| 1467 | if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) { |
| 1468 | /* Server key has bigger modulus. */ |
| 1469 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < |
| 1470 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) { |
| 1471 | fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", |
| 1472 | get_remote_ipaddr(), |
| 1473 | BN_num_bits(sensitive_data.server_key->rsa->n), |
| 1474 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), |
| 1475 | SSH_KEY_BITS_RESERVED); |
| 1476 | } |
| 1477 | if (rsa_private_decrypt(session_key_int, session_key_int, |
| 1478 | sensitive_data.server_key->rsa) <= 0) |
| 1479 | rsafail++; |
| 1480 | if (rsa_private_decrypt(session_key_int, session_key_int, |
| 1481 | sensitive_data.ssh1_host_key->rsa) <= 0) |
| 1482 | rsafail++; |
| 1483 | } else { |
| 1484 | /* Host key has bigger modulus (or they are equal). */ |
| 1485 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < |
| 1486 | BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) { |
| 1487 | fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", |
| 1488 | get_remote_ipaddr(), |
| 1489 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), |
| 1490 | BN_num_bits(sensitive_data.server_key->rsa->n), |
| 1491 | SSH_KEY_BITS_RESERVED); |
| 1492 | } |
| 1493 | if (rsa_private_decrypt(session_key_int, session_key_int, |
| 1494 | sensitive_data.ssh1_host_key->rsa) < 0) |
| 1495 | rsafail++; |
| 1496 | if (rsa_private_decrypt(session_key_int, session_key_int, |
| 1497 | sensitive_data.server_key->rsa) < 0) |
| 1498 | rsafail++; |
| 1499 | } |
| 1500 | return (rsafail); |
| 1501 | } |
| 1502 | /* |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 1503 | * SSH1 key exchange |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1504 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 1505 | static void |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 1506 | do_ssh1_kex(void) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1507 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1508 | int i, len; |
Damien Miller | 7650bc6 | 2001-01-30 09:27:26 +1100 | [diff] [blame] | 1509 | int rsafail = 0; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1510 | BIGNUM *session_key_int; |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 1511 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
| 1512 | u_char cookie[8]; |
| 1513 | u_int cipher_type, auth_mask, protocol_flags; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1514 | u_int32_t rand = 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1515 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1516 | /* |
| 1517 | * Generate check bytes that the client must send back in the user |
| 1518 | * packet in order for it to be accepted; this is used to defy ip |
| 1519 | * spoofing attacks. Note that this only works against somebody |
| 1520 | * doing IP spoofing from a remote machine; any machine on the local |
| 1521 | * network can still see outgoing packets and catch the random |
| 1522 | * cookie. This only affects rhosts authentication, and this is one |
| 1523 | * of the reasons why it is inherently insecure. |
| 1524 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1525 | for (i = 0; i < 8; i++) { |
| 1526 | if (i % 4 == 0) |
| 1527 | rand = arc4random(); |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 1528 | cookie[i] = rand & 0xff; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1529 | rand >>= 8; |
| 1530 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1531 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1532 | /* |
| 1533 | * Send our public key. We include in the packet 64 bits of random |
| 1534 | * data that must be matched in the reply in order to prevent IP |
| 1535 | * spoofing. |
| 1536 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1537 | packet_start(SSH_SMSG_PUBLIC_KEY); |
| 1538 | for (i = 0; i < 8; i++) |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 1539 | packet_put_char(cookie[i]); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1540 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1541 | /* Store our public server RSA key. */ |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 1542 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
| 1543 | packet_put_bignum(sensitive_data.server_key->rsa->e); |
| 1544 | packet_put_bignum(sensitive_data.server_key->rsa->n); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1545 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1546 | /* Store our public host RSA key. */ |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 1547 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
| 1548 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); |
| 1549 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1550 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1551 | /* Put protocol flags. */ |
| 1552 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1553 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1554 | /* Declare which ciphers we support. */ |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 1555 | packet_put_int(cipher_mask_ssh1(0)); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1556 | |
| 1557 | /* Declare supported authentication types. */ |
| 1558 | auth_mask = 0; |
| 1559 | if (options.rhosts_authentication) |
| 1560 | auth_mask |= 1 << SSH_AUTH_RHOSTS; |
| 1561 | if (options.rhosts_rsa_authentication) |
| 1562 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; |
| 1563 | if (options.rsa_authentication) |
| 1564 | auth_mask |= 1 << SSH_AUTH_RSA; |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 1565 | #if defined(KRB4) || defined(KRB5) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1566 | if (options.kerberos_authentication) |
| 1567 | auth_mask |= 1 << SSH_AUTH_KERBEROS; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1568 | #endif |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 1569 | #if defined(AFS) || defined(KRB5) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1570 | if (options.kerberos_tgt_passing) |
| 1571 | auth_mask |= 1 << SSH_PASS_KERBEROS_TGT; |
Ben Lindstrom | ec95ed9 | 2001-07-04 04:21:14 +0000 | [diff] [blame] | 1572 | #endif |
| 1573 | #ifdef AFS |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1574 | if (options.afs_token_passing) |
| 1575 | auth_mask |= 1 << SSH_PASS_AFS_TOKEN; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1576 | #endif |
Ben Lindstrom | 551ea37 | 2001-06-05 18:56:16 +0000 | [diff] [blame] | 1577 | if (options.challenge_response_authentication == 1) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1578 | auth_mask |= 1 << SSH_AUTH_TIS; |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1579 | if (options.password_authentication) |
| 1580 | auth_mask |= 1 << SSH_AUTH_PASSWORD; |
| 1581 | packet_put_int(auth_mask); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1582 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1583 | /* Send the packet and wait for it to be sent. */ |
| 1584 | packet_send(); |
| 1585 | packet_write_wait(); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1586 | |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 1587 | debug("Sent %d bit server key and %d bit host key.", |
| 1588 | BN_num_bits(sensitive_data.server_key->rsa->n), |
| 1589 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1590 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1591 | /* Read clients reply (cipher type and session key). */ |
Damien Miller | dff5099 | 2002-01-22 23:16:32 +1100 | [diff] [blame] | 1592 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1593 | |
Damien Miller | 50945fa | 1999-12-09 10:31:37 +1100 | [diff] [blame] | 1594 | /* Get cipher type and check whether we accept this. */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1595 | cipher_type = packet_get_char(); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1596 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 1597 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
Damien Miller | 50945fa | 1999-12-09 10:31:37 +1100 | [diff] [blame] | 1598 | packet_disconnect("Warning: client selects unsupported cipher."); |
| 1599 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1600 | /* Get check bytes from the packet. These must match those we |
| 1601 | sent earlier with the public key packet. */ |
| 1602 | for (i = 0; i < 8; i++) |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 1603 | if (cookie[i] != packet_get_char()) |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1604 | packet_disconnect("IP Spoofing check bytes do not match."); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1605 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1606 | debug("Encryption type: %.200s", cipher_name(cipher_type)); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1607 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1608 | /* Get the encrypted integer. */ |
Damien Miller | da75516 | 2002-01-22 23:09:22 +1100 | [diff] [blame] | 1609 | if ((session_key_int = BN_new()) == NULL) |
| 1610 | fatal("do_ssh1_kex: BN_new failed"); |
Damien Miller | d432ccf | 2002-01-22 23:14:44 +1100 | [diff] [blame] | 1611 | packet_get_bignum(session_key_int); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1612 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1613 | protocol_flags = packet_get_int(); |
| 1614 | packet_set_protocol_flags(protocol_flags); |
Damien Miller | 48b03fc | 2002-01-22 23:11:40 +1100 | [diff] [blame] | 1615 | packet_check_eom(); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1616 | |
Ben Lindstrom | abcb145 | 2002-03-22 01:10:21 +0000 | [diff] [blame] | 1617 | /* Decrypt session_key_int using host/server keys */ |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 1618 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
| 1619 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 1620 | /* |
| 1621 | * Extract session key from the decrypted integer. The key is in the |
| 1622 | * least significant 256 bits of the integer; the first byte of the |
| 1623 | * key is in the highest bits. |
| 1624 | */ |
Damien Miller | 7650bc6 | 2001-01-30 09:27:26 +1100 | [diff] [blame] | 1625 | if (!rsafail) { |
| 1626 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); |
| 1627 | len = BN_num_bytes(session_key_int); |
| 1628 | if (len < 0 || len > sizeof(session_key)) { |
| 1629 | error("do_connection: bad session key len from %s: " |
Ben Lindstrom | 31ca54a | 2001-02-09 02:11:24 +0000 | [diff] [blame] | 1630 | "session_key_int %d > sizeof(session_key) %lu", |
| 1631 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); |
Damien Miller | 7650bc6 | 2001-01-30 09:27:26 +1100 | [diff] [blame] | 1632 | rsafail++; |
| 1633 | } else { |
| 1634 | memset(session_key, 0, sizeof(session_key)); |
| 1635 | BN_bn2bin(session_key_int, |
| 1636 | session_key + sizeof(session_key) - len); |
Ben Lindstrom | eb648a7 | 2001-03-05 06:00:29 +0000 | [diff] [blame] | 1637 | |
| 1638 | compute_session_id(session_id, cookie, |
| 1639 | sensitive_data.ssh1_host_key->rsa->n, |
| 1640 | sensitive_data.server_key->rsa->n); |
| 1641 | /* |
| 1642 | * Xor the first 16 bytes of the session key with the |
| 1643 | * session id. |
| 1644 | */ |
| 1645 | for (i = 0; i < 16; i++) |
| 1646 | session_key[i] ^= session_id[i]; |
Damien Miller | 7650bc6 | 2001-01-30 09:27:26 +1100 | [diff] [blame] | 1647 | } |
| 1648 | } |
| 1649 | if (rsafail) { |
Ben Lindstrom | eb648a7 | 2001-03-05 06:00:29 +0000 | [diff] [blame] | 1650 | int bytes = BN_num_bytes(session_key_int); |
Ben Lindstrom | 13c5d3b | 2002-02-26 18:00:48 +0000 | [diff] [blame] | 1651 | u_char *buf = xmalloc(bytes); |
Ben Lindstrom | eb648a7 | 2001-03-05 06:00:29 +0000 | [diff] [blame] | 1652 | MD5_CTX md; |
| 1653 | |
Damien Miller | 7650bc6 | 2001-01-30 09:27:26 +1100 | [diff] [blame] | 1654 | log("do_connection: generating a fake encryption key"); |
Ben Lindstrom | eb648a7 | 2001-03-05 06:00:29 +0000 | [diff] [blame] | 1655 | BN_bn2bin(session_key_int, buf); |
| 1656 | MD5_Init(&md); |
| 1657 | MD5_Update(&md, buf, bytes); |
| 1658 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); |
| 1659 | MD5_Final(session_key, &md); |
| 1660 | MD5_Init(&md); |
| 1661 | MD5_Update(&md, session_key, 16); |
| 1662 | MD5_Update(&md, buf, bytes); |
| 1663 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); |
| 1664 | MD5_Final(session_key + 16, &md); |
| 1665 | memset(buf, 0, bytes); |
| 1666 | xfree(buf); |
Ben Lindstrom | 941ac82 | 2001-03-05 06:25:23 +0000 | [diff] [blame] | 1667 | for (i = 0; i < 16; i++) |
| 1668 | session_id[i] = session_key[i] ^ session_key[i + 16]; |
Damien Miller | 7650bc6 | 2001-01-30 09:27:26 +1100 | [diff] [blame] | 1669 | } |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 1670 | /* Destroy the private and public keys. No longer. */ |
Damien Miller | 3a5b023 | 2002-03-13 13:19:42 +1100 | [diff] [blame] | 1671 | destroy_sensitive_data(); |
Ben Lindstrom | eb648a7 | 2001-03-05 06:00:29 +0000 | [diff] [blame] | 1672 | |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 1673 | if (use_privsep) |
| 1674 | mm_ssh1_session_id(session_id); |
| 1675 | |
Damien Miller | 396691a | 2000-01-20 22:44:08 +1100 | [diff] [blame] | 1676 | /* Destroy the decrypted integer. It is no longer needed. */ |
| 1677 | BN_clear_free(session_key_int); |
| 1678 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1679 | /* Set the session key. From this on all communications will be encrypted. */ |
| 1680 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1681 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1682 | /* Destroy our copy of the session key. It is no longer needed. */ |
| 1683 | memset(session_key, 0, sizeof(session_key)); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1684 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1685 | debug("Received session key; encryption turned on."); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1686 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 1687 | /* Send an acknowledgement packet. Note that this packet is sent encrypted. */ |
| 1688 | packet_start(SSH_SMSG_SUCCESS); |
| 1689 | packet_send(); |
| 1690 | packet_write_wait(); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1691 | } |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 1692 | |
| 1693 | /* |
| 1694 | * SSH2 key exchange: diffie-hellman-group1-sha1 |
| 1695 | */ |
Ben Lindstrom | bba8121 | 2001-06-25 05:01:22 +0000 | [diff] [blame] | 1696 | static void |
Ben Lindstrom | 46c1622 | 2000-12-22 01:43:59 +0000 | [diff] [blame] | 1697 | do_ssh2_kex(void) |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 1698 | { |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 1699 | Kex *kex; |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 1700 | |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 1701 | if (options.ciphers != NULL) { |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 1702 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
Damien Miller | 7892879 | 2000-04-12 20:17:38 +1000 | [diff] [blame] | 1703 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
| 1704 | } |
Damien Miller | a0ff466 | 2001-03-30 10:49:35 +1000 | [diff] [blame] | 1705 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
| 1706 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); |
| 1707 | myproposal[PROPOSAL_ENC_ALGS_STOC] = |
| 1708 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); |
| 1709 | |
Ben Lindstrom | 06b33aa | 2001-02-15 03:01:59 +0000 | [diff] [blame] | 1710 | if (options.macs != NULL) { |
| 1711 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = |
| 1712 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; |
| 1713 | } |
Damien Miller | 0bc1bd8 | 2000-11-13 22:57:25 +1100 | [diff] [blame] | 1714 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
| 1715 | |
Ben Lindstrom | 8ac9106 | 2001-04-04 17:57:54 +0000 | [diff] [blame] | 1716 | /* start key exchange */ |
Ben Lindstrom | 238abf6 | 2001-04-04 17:52:53 +0000 | [diff] [blame] | 1717 | kex = kex_setup(myproposal); |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 1718 | kex->server = 1; |
| 1719 | kex->client_version_string=client_version_string; |
| 1720 | kex->server_version_string=server_version_string; |
| 1721 | kex->load_host_key=&get_hostkey_by_type; |
Ben Lindstrom | 7a2073c | 2002-03-22 02:30:41 +0000 | [diff] [blame] | 1722 | kex->host_key_index=&get_hostkey_index; |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 1723 | |
Ben Lindstrom | 8ac9106 | 2001-04-04 17:57:54 +0000 | [diff] [blame] | 1724 | xxx_kex = kex; |
| 1725 | |
Ben Lindstrom | be2cc43 | 2001-04-04 23:46:07 +0000 | [diff] [blame] | 1726 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 1727 | |
Ben Lindstrom | 2d90e00 | 2001-04-04 02:00:54 +0000 | [diff] [blame] | 1728 | session_id2 = kex->session_id; |
| 1729 | session_id2_len = kex->session_id_len; |
| 1730 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 1731 | #ifdef DEBUG_KEXDH |
| 1732 | /* send 1st encrypted/maced/compressed message */ |
| 1733 | packet_start(SSH2_MSG_IGNORE); |
| 1734 | packet_put_cstring("markus"); |
| 1735 | packet_send(); |
| 1736 | packet_write_wait(); |
| 1737 | #endif |
Ben Lindstrom | 20d7c7b | 2001-04-04 01:56:17 +0000 | [diff] [blame] | 1738 | debug("KEX done"); |
Damien Miller | efb4afe | 2000-04-12 18:45:05 +1000 | [diff] [blame] | 1739 | } |